Animating by calling invalidate() from draw(),loading and drawing resources, handling onPause() in an animation
/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package app.test;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.TextView;
/**
* View that draws, takes keystrokes, etc. for a simple LunarLander game.
*
* Has a mode which RUNNING, PAUSED, etc. Has a x, y, dx, dy, ... capturing the
* current ship physics. All x/y etc. are measured with (0,0) at the lower left.
* updatePhysics() advances the physics based on realtime. draw() renders the
* ship, and does an invalidate() to prompt another draw() as soon as possible
* by the system.
*/
class LunarView extends SurfaceView implements SurfaceHolder.Callback {
class LunarThread extends Thread {
/*
* Difficulty setting constants
*/
public static final int DIFFICULTY_EASY = 0;
public static final int DIFFICULTY_HARD = 1;
public static final int DIFFICULTY_MEDIUM = 2;
/*
* Physics constants
*/
public static final int PHYS_DOWN_ACCEL_SEC = 35;
public static final int PHYS_FIRE_ACCEL_SEC = 80;
public static final int PHYS_FUEL_INIT = 60;
public static final int PHYS_FUEL_MAX = 100;
public static final int PHYS_FUEL_SEC = 10;
public static final int PHYS_SLEW_SEC = 120; // degrees/second rotate
public static final int PHYS_SPEED_HYPERSPACE = 180;
public static final int PHYS_SPEED_INIT = 30;
public static final int PHYS_SPEED_MAX = 120;
/*
* State-tracking constants
*/
public static final int STATE_LOSE = 1;
public static final int STATE_PAUSE = 2;
public static final int STATE_READY = 3;
public static final int STATE_RUNNING = 4;
public static final int STATE_WIN = 5;
/*
* Goal condition constants
*/
public static final int TARGET_ANGLE = 18; // > this angle means crash
public static final int TARGET_BOTTOM_PADDING = 17; // px below gear
public static final int TARGET_PAD_HEIGHT = 8; // how high above ground
public static final int TARGET_SPEED = 28; // > this speed means crash
public static final double TARGET_WIDTH = 1.6; // width of target
/*
* UI constants (i.e. the speed & fuel bars)
*/
public static final int UI_BAR = 100; // width of the bar(s)
public static final int UI_BAR_HEIGHT = 10; // height of the bar(s)
private static final String KEY_DIFFICULTY = "mDifficulty";
private static final String KEY_DX = "mDX";
private static final String KEY_DY = "mDY";
private static final String KEY_FUEL = "mFuel";
private static final String KEY_GOAL_ANGLE = "mGoalAngle";
private static final String KEY_GOAL_SPEED = "mGoalSpeed";
private static final String KEY_GOAL_WIDTH = "mGoalWidth";
private static final String KEY_GOAL_X = "mGoalX";
private static final String KEY_HEADING = "mHeading";
private static final String KEY_LANDER_HEIGHT = "mLanderHeight";
private static final String KEY_LANDER_WIDTH = "mLanderWidth";
private static final String KEY_WINS = "mWinsInARow";
private static final String KEY_X = "mX";
private static final String KEY_Y = "mY";
/*
* Member (state) fields
*/
/** The drawable to use as the background of the animation canvas */
private Bitmap mBackgroundImage;
/**
* Current height of the surface/canvas.
*
* @see #setSurfaceSize
*/
private int mCanvasHeight = 1;
/**
* Current width of the surface/canvas.
*
* @see #setSurfaceSize
*/
private int mCanvasWidth = 1;
/** What to draw for the Lander when it has crashed */
private Drawable mCrashedImage;
/**
* Current difficulty -- amount of fuel, allowed angle, etc. Default is
* MEDIUM.
*/
private int mDifficulty;
/** Velocity dx. */
private double mDX;
/** Velocity dy. */
private double mDY;
/** Is the engine burning? */
private boolean mEngineFiring;
/** What to draw for the Lander when the engine is firing */
private Drawable mFiringImage;
/** Fuel remaining */
private double mFuel;
/** Allowed angle. */
private int mGoalAngle;
/** Allowed speed. */
private int mGoalSpeed;
/** Width of the landing pad. */
private int mGoalWidth;
/** X of the landing pad. */
private int mGoalX;
/** Message handler used by thread to interact with TextView */
private Handler mHandler;
/**
* Lander heading in degrees, with 0 up, 90 right. Kept in the range
* 0..360.
*/
private double mHeading;
/** Pixel height of lander image. */
private int mLanderHeight;
/** What to draw for the Lander in its normal state */
private Drawable mLanderImage;
/** Pixel width of lander image. */
private int mLanderWidth;
/** Used to figure out elapsed time between frames */
private long mLastTime;
/** Paint to draw the lines on screen. */
private Paint mLinePaint;
/** "Bad" speed-too-high variant of the line color. */
private Paint mLinePaintBad;
/** The state of the game. One of READY, RUNNING, PAUSE, LOSE, or WIN */
private int mMode;
/** Currently rotating, -1 left, 0 none, 1 right. */
private int mRotating;
/** Indicate whether the surface has been created & is ready to draw */
private boolean mRun = false;
/** Scratch rect object. */
private RectF mScratchRect;
/** Handle to the surface manager object we interact with */
private SurfaceHolder mSurfaceHolder;
/** Number of wins in a row. */
private int mWinsInARow;
/** X of lander center. */
private double mX;
/** Y of lander center. */
private double mY;
public LunarThread(SurfaceHolder surfaceHolder, Context context,
Handler handler) {
// get handles to some important objects
mSurfaceHolder = surfaceHolder;
mHandler = handler;
mContext = context;
Resources res = context.getResources();
// cache handles to our key sprites & other drawables
mLanderImage = context.getResources().getDrawable(
R.drawable.lander_plain);
mFiringImage = context.getResources().getDrawable(
R.drawable.lander_firing);
mCrashedImage = context.getResources().getDrawable(
R.drawable.lander_crashed);
// load background image as a Bitmap instead of a Drawable b/c
// we don't need to transform it and it's faster to draw this way
mBackgroundImage = BitmapFactory.decodeResource(res,
R.drawable.earthrise);
// Use the regular lander image as the model size for all sprites
mLanderWidth = mLanderImage.getIntrinsicWidth();
mLanderHeight = mLanderImage.getIntrinsicHeight();
// Initialize paints for speedometer
mLinePaint = new Paint();
mLinePaint.setAntiAlias(true);
mLinePaint.setARGB(255, 0, 255, 0);
mLinePaintBad = new Paint();
mLinePaintBad.setAntiAlias(true);
mLinePaintBad.setARGB(255, 120, 180, 0);
mScratchRect = new RectF(0, 0, 0, 0);
mWinsInARow = 0;
mDifficulty = DIFFICULTY_MEDIUM;
// initial show-up of lander (not yet playing)
mX = mLanderWidth;
mY = mLanderHeight * 2;
mFuel = PHYS_FUEL_INIT;
mDX = 0;
mDY = 0;
mHeading = 0;
mEngineFiring = true;
}
/**
* Starts the game, setting parameters for the current difficulty.
*/
public void doStart() {
synchronized (mSurfaceHolder) {
// First set the game for Medium difficulty
mFuel = PHYS_FUEL_INIT;
mEngineFiring = false;
mGoalWidth = (int) (mLanderWidth * TARGET_WIDTH);
mGoalSpeed = TARGET_SPEED;
mGoalAngle = TARGET_ANGLE;
int speedInit = PHYS_SPEED_INIT;
// Adjust difficulty params for EASY/HARD
if (mDifficulty == DIFFICULTY_EASY) {
mFuel = mFuel * 3 / 2;
mGoalWidth = mGoalWidth * 4 / 3;
mGoalSpeed = mGoalSpeed * 3 / 2;
mGoalAngle = mGoalAngle * 4 / 3;
speedInit = speedInit * 3 / 4;
} else if (mDifficulty == DIFFICULTY_HARD) {
mFuel = mFuel * 7 / 8;
mGoalWidth = mGoalWidth * 3 / 4;
mGoalSpeed = mGoalSpeed * 7 / 8;
speedInit = speedInit * 4 / 3;
}
// pick a convenient initial location for the lander sprite
mX = mCanvasWidth / 2;
mY = mCanvasHeight - mLanderHeight / 2;
// start with a little random motion
mDY = Math.random() * -speedInit;
mDX = Math.random() * 2 * speedInit - speedInit;
mHeading = 0;
// Figure initial spot for landing, not too near center
while (true) {
mGoalX = (int) (Math.random() * (mCanvasWidth - mGoalWidth));
if (Math.abs(mGoalX - (mX - mLanderWidth / 2)) > mCanvasHeight / 6)
break;
}
mLastTime = System.currentTimeMillis() + 100;
setState(STATE_RUNNING);
}
}
/**
* Pauses the physics update & animation.
*/
public void pause() {
synchronized (mSurfaceHolder) {
if (mMode == STATE_RUNNING) setState(STATE_PAUSE);
}
}
/**
* Restores game state from the indicated Bundle. Typically called when
* the Activity is being restored after having been previously
* destroyed.
*
* @param savedState Bundle containing the game state
*/
public synchronized void restoreState(Bundle savedState) {
synchronized (mSurfaceHolder) {
setState(STATE_PAUSE);
mRotating = 0;
mEngineFiring = false;
mDifficulty = savedState.getInt(KEY_DIFFICULTY);
mX = savedState.getDouble(KEY_X);
mY = savedState.getDouble(KEY_Y);
mDX = savedState.getDouble(KEY_DX);
mDY = savedState.getDouble(KEY_DY);
mHeading = savedState.getDouble(KEY_HEADING);
mLanderWidth = savedState.getInt(KEY_LANDER_WIDTH);
mLanderHeight = savedState.getInt(KEY_LANDER_HEIGHT);
mGoalX = savedState.getInt(KEY_GOAL_X);
mGoalSpeed = savedState.getInt(KEY_GOAL_SPEED);
mGoalAngle = savedState.getInt(KEY_GOAL_ANGLE);
mGoalWidth = savedState.getInt(KEY_GOAL_WIDTH);
mWinsInARow = savedState.getInt(KEY_WINS);
mFuel = savedState.getDouble(KEY_FUEL);
}
}
@Override
public void run() {
while (mRun) {
Canvas c = null;
try {
c = mSurfaceHolder.lockCanvas(null);
synchronized (mSurfaceHolder) {
if (mMode == STATE_RUNNING) updatePhysics();
doDraw(c);
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
mSurfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
/**
* Dump game state to the provided Bundle. Typically called when the
* Activity is being suspended.
*
* @return Bundle with this view's state
*/
public Bundle saveState(Bundle map) {
synchronized (mSurfaceHolder) {
if (map != null) {
map.putInt(KEY_DIFFICULTY, Integer.valueOf(mDifficulty));
map.putDouble(KEY_X, Double.valueOf(mX));
map.putDouble(KEY_Y, Double.valueOf(mY));
map.putDouble(KEY_DX, Double.valueOf(mDX));
map.putDouble(KEY_DY, Double.valueOf(mDY));
map.putDouble(KEY_HEADING, Double.valueOf(mHeading));
map.putInt(KEY_LANDER_WIDTH, Integer.valueOf(mLanderWidth));
map.putInt(KEY_LANDER_HEIGHT, Integer
.valueOf(mLanderHeight));
map.putInt(KEY_GOAL_X, Integer.valueOf(mGoalX));
map.putInt(KEY_GOAL_SPEED, Integer.valueOf(mGoalSpeed));
map.putInt(KEY_GOAL_ANGLE, Integer.valueOf(mGoalAngle));
map.putInt(KEY_GOAL_WIDTH, Integer.valueOf(mGoalWidth));
map.putInt(KEY_WINS, Integer.valueOf(mWinsInARow));
map.putDouble(KEY_FUEL, Double.valueOf(mFuel));
}
}
return map;
}
/**
* Sets the current difficulty.
*
* @param difficulty
*/
public void setDifficulty(int difficulty) {
synchronized (mSurfaceHolder) {
mDifficulty = difficulty;
}
}
/**
* Sets if the engine is currently firing.
*/
public void setFiring(boolean firing) {
synchronized (mSurfaceHolder) {
mEngineFiring = firing;
}
}
/**
* Used to signal the thread whether it should be running or not.
* Passing true allows the thread to run; passing false will shut it
* down if it's already running. Calling start() after this was most
* recently called with false will result in an immediate shutdown.
*
* @param b true to run, false to shut down
*/
public void setRunning(boolean b) {
mRun = b;
}
/**
* Sets the game mode. That is, whether we are running, paused, in the
* failure state, in the victory state, etc.
*
* @see #setState(int, CharSequence)
* @param mode one of the STATE_* constants
*/
public void setState(int mode) {
synchronized (mSurfaceHolder) {
setState(mode, null);
}
}
/**
* Sets the game mode. That is, whether we are running, paused, in the
* failure state, in the victory state, etc.
*
* @param mode one of the STATE_* constants
* @param message string to add to screen or null
*/
public void setState(int mode, CharSequence message) {
/*
* This method optionally can cause a text message to be displayed
* to the user when the mode changes. Since the View that actually
* renders that text is part of the main View hierarchy and not
* owned by this thread, we can't touch the state of that View.
* Instead we use a Message + Handler to relay commands to the main
* thread, which updates the user-text View.
*/
synchronized (mSurfaceHolder) {
mMode = mode;
if (mMode == STATE_RUNNING) {
Message msg = mHandler.obtainMessage();
Bundle b = new Bundle();
b.putString("text", "");
b.putInt("viz", View.INVISIBLE);
msg.setData(b);
mHandler.sendMessage(msg);
} else {
mRotating = 0;
mEngineFiring = false;
Resources res = mContext.getResources();
CharSequence str = "";
if (mMode == STATE_READY)
str = res.getText(R.string.mode_ready);
else if (mMode == STATE_PAUSE)
str = res.getText(R.string.mode_pause);
else if (mMode == STATE_LOSE)
str = res.getText(R.string.mode_lose);
else if (mMode == STATE_WIN)
str = res.getString(R.string.mode_win_prefix)
+ mWinsInARow + " "
+ res.getString(R.string.mode_win_suffix);
if (message != null) {
str = message + "\n" + str;
}
if (mMode == STATE_LOSE) mWinsInARow = 0;
Message msg = mHandler.obtainMessage();
Bundle b = new Bundle();
b.putString("text", str.toString());
b.putInt("viz", View.VISIBLE);
msg.setData(b);
mHandler.sendMessage(msg);
}
}
}
/* Callback invoked when the surface dimensions change. */
public void setSurfaceSize(int width, int height) {
// synchronized to make sure these all change atomically
synchronized (mSurfaceHolder) {
mCanvasWidth = width;
mCanvasHeight = height;
// don't forget to resize the background image
mBackgroundImage = Bitmap.createScaledBitmap(
mBackgroundImage, width, height, true);
}
}
/**
* Resumes from a pause.
*/
public void unpause() {
// Move the real time clock up to now
synchronized (mSurfaceHolder) {
mLastTime = System.currentTimeMillis() + 100;
}
setState(STATE_RUNNING);
}
/**
* Handles a key-down event.
*
* @param keyCode the key that was pressed
* @param msg the original event object
* @return true
*/
boolean doKeyDown(int keyCode, KeyEvent msg) {
synchronized (mSurfaceHolder) {
boolean okStart = false;
if (keyCode == KeyEvent.KEYCODE_DPAD_UP) okStart = true;
if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) okStart = true;
if (keyCode == KeyEvent.KEYCODE_S) okStart = true;
if (okStart
&& (mMode == STATE_READY || mMode == STATE_LOSE || mMode == STATE_WIN)) {
// ready-to-start -> start
doStart();
return true;
} else if (mMode == STATE_PAUSE && okStart) {
// paused -> running
unpause();
return true;
} else if (mMode == STATE_RUNNING) {
// center/space -> fire
if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER
|| keyCode == KeyEvent.KEYCODE_SPACE) {
setFiring(true);
return true;
// left/q -> left
} else if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT
|| keyCode == KeyEvent.KEYCODE_Q) {
mRotating = -1;
return true;
// right/w -> right
} else if (keyCode == KeyEvent.KEYCODE_DPAD_RIGHT
|| keyCode == KeyEvent.KEYCODE_W) {
mRotating = 1;
return true;
// up -> pause
} else if (keyCode == KeyEvent.KEYCODE_DPAD_UP) {
pause();
return true;
}
}
return false;
}
}
/**
* Handles a key-up event.
*
* @param keyCode the key that was pressed
* @param msg the original event object
* @return true if the key was handled and consumed, or else false
*/
boolean doKeyUp(int keyCode, KeyEvent msg) {
boolean handled = false;
synchronized (mSurfaceHolder) {
if (mMode == STATE_RUNNING) {
if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER
|| keyCode == KeyEvent.KEYCODE_SPACE) {
setFiring(false);
handled = true;
} else if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT
|| keyCode == KeyEvent.KEYCODE_Q
|| keyCode == KeyEvent.KEYCODE_DPAD_RIGHT
|| keyCode == KeyEvent.KEYCODE_W) {
mRotating = 0;
handled = true;
}
}
}
return handled;
}
/**
* Draws the ship, fuel/speed bars, and background to the provided
* Canvas.
*/
private void doDraw(Canvas canvas) {
// Draw the background image. Operations on the Canvas accumulate
// so this is like clearing the screen.
canvas.drawBitmap(mBackgroundImage, 0, 0, null);
int yTop = mCanvasHeight - ((int) mY + mLanderHeight / 2);
int xLeft = (int) mX - mLanderWidth / 2;
// Draw the fuel gauge
int fuelWidth = (int) (UI_BAR * mFuel / PHYS_FUEL_MAX);
mScratchRect.set(4, 4, 4 + fuelWidth, 4 + UI_BAR_HEIGHT);
canvas.drawRect(mScratchRect, mLinePaint);
// Draw the speed gauge, with a two-tone effect
double speed = Math.sqrt(mDX * mDX + mDY * mDY);
int speedWidth = (int) (UI_BAR * speed / PHYS_SPEED_MAX);
if (speed <= mGoalSpeed) {
mScratchRect.set(4 + UI_BAR + 4, 4,
4 + UI_BAR + 4 + speedWidth, 4 + UI_BAR_HEIGHT);
canvas.drawRect(mScratchRect, mLinePaint);
} else {
// Draw the bad color in back, with the good color in front of
// it
mScratchRect.set(4 + UI_BAR + 4, 4,
4 + UI_BAR + 4 + speedWidth, 4 + UI_BAR_HEIGHT);
canvas.drawRect(mScratchRect, mLinePaintBad);
int goalWidth = (UI_BAR * mGoalSpeed / PHYS_SPEED_MAX);
mScratchRect.set(4 + UI_BAR + 4, 4, 4 + UI_BAR + 4 + goalWidth,
4 + UI_BAR_HEIGHT);
canvas.drawRect(mScratchRect, mLinePaint);
}
// Draw the landing pad
canvas.drawLine(mGoalX, 1 + mCanvasHeight - TARGET_PAD_HEIGHT,
mGoalX + mGoalWidth, 1 + mCanvasHeight - TARGET_PAD_HEIGHT,
mLinePaint);
// Draw the ship with its current rotation
canvas.save();
canvas.rotate((float) mHeading, (float) mX, mCanvasHeight
- (float) mY);
if (mMode == STATE_LOSE) {
mCrashedImage.setBounds(xLeft, yTop, xLeft + mLanderWidth, yTop
+ mLanderHeight);
mCrashedImage.draw(canvas);
} else if (mEngineFiring) {
mFiringImage.setBounds(xLeft, yTop, xLeft + mLanderWidth, yTop
+ mLanderHeight);
mFiringImage.draw(canvas);
} else {
mLanderImage.setBounds(xLeft, yTop, xLeft + mLanderWidth, yTop
+ mLanderHeight);
mLanderImage.draw(canvas);
}
canvas.restore();
}
/**
* Figures the lander state (x, y, fuel, ...) based on the passage of
* realtime. Does not invalidate(). Called at the start of draw().
* Detects the end-of-game and sets the UI to the next state.
*/
private void updatePhysics() {
long now = System.currentTimeMillis();
// Do nothing if mLastTime is in the future.
// This allows the game-start to delay the start of the physics
// by 100ms or whatever.
if (mLastTime > now) return;
double elapsed = (now - mLastTime) / 1000.0;
// mRotating -- update heading
if (mRotating != 0) {
mHeading += mRotating * (PHYS_SLEW_SEC * elapsed);
// Bring things back into the range 0..360
if (mHeading < 0)
mHeading += 360;
else if (mHeading >= 360) mHeading -= 360;
}
// Base accelerations -- 0 for x, gravity for y
double ddx = 0.0;
double ddy = -PHYS_DOWN_ACCEL_SEC * elapsed;
if (mEngineFiring) {
// taking 0 as up, 90 as to the right
// cos(deg) is ddy component, sin(deg) is ddx component
double elapsedFiring = elapsed;
double fuelUsed = elapsedFiring * PHYS_FUEL_SEC;
// tricky case where we run out of fuel partway through the
// elapsed
if (fuelUsed > mFuel) {
elapsedFiring = mFuel / fuelUsed * elapsed;
fuelUsed = mFuel;
// Oddball case where we adjust the "control" from here
mEngineFiring = false;
}
mFuel -= fuelUsed;
// have this much acceleration from the engine
double accel = PHYS_FIRE_ACCEL_SEC * elapsedFiring;
double radians = 2 * Math.PI * mHeading / 360;
ddx = Math.sin(radians) * accel;
ddy += Math.cos(radians) * accel;
}
double dxOld = mDX;
double dyOld = mDY;
// figure speeds for the end of the period
mDX += ddx;
mDY += ddy;
// figure position based on average speed during the period
mX += elapsed * (mDX + dxOld) / 2;
mY += elapsed * (mDY + dyOld) / 2;
mLastTime = now;
// Evaluate if we have landed ... stop the game
double yLowerBound = TARGET_PAD_HEIGHT + mLanderHeight / 2
- TARGET_BOTTOM_PADDING;
if (mY <= yLowerBound) {
mY = yLowerBound;
int result = STATE_LOSE;
CharSequence message = "";
Resources res = mContext.getResources();
double speed = Math.sqrt(mDX * mDX + mDY * mDY);
boolean onGoal = (mGoalX <= mX - mLanderWidth / 2 && mX
+ mLanderWidth / 2 <= mGoalX + mGoalWidth);
// "Hyperspace" win -- upside down, going fast,
// puts you back at the top.
if (onGoal && Math.abs(mHeading - 180) < mGoalAngle
&& speed > PHYS_SPEED_HYPERSPACE) {
result = STATE_WIN;
mWinsInARow++;
doStart();
return;
// Oddball case: this case does a return, all other cases
// fall through to setMode() below.
} else if (!onGoal) {
message = res.getText(R.string.message_off_pad);
} else if (!(mHeading <= mGoalAngle || mHeading >= 360 - mGoalAngle)) {
message = res.getText(R.string.message_bad_angle);
} else if (speed > mGoalSpeed) {
message = res.getText(R.string.message_too_fast);
} else {
result = STATE_WIN;
mWinsInARow++;
}
setState(result, message);
}
}
}
/** Handle to the application context, used to e.g. fetch Drawables. */
private Context mContext;
/** Pointer to the text view to display "Paused.." etc. */
private TextView mStatusText;
/** The thread that actually draws the animation */
private LunarThread thread;
public LunarView(Context context, AttributeSet attrs) {
super(context, attrs);
// register our interest in hearing about changes to our surface
SurfaceHolder holder = getHolder();
holder.addCallback(this);
// create thread only; it's started in surfaceCreated()
thread = new LunarThread(holder, context, new Handler() {
@Override
public void handleMessage(Message m) {
mStatusText.setVisibility(m.getData().getInt("viz"));
mStatusText.setText(m.getData().getString("text"));
}
});
setFocusable(true); // make sure we get key events
}
/**
* Fetches the animation thread corresponding to this LunarView.
*
* @return the animation thread
*/
public LunarThread getThread() {
return thread;
}
/**
* Standard override to get key-press events.
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent msg) {
return thread.doKeyDown(keyCode, msg);
}
/**
* Standard override for key-up. We actually care about these, so we can
* turn off the engine or stop rotating.
*/
@Override
public boolean onKeyUp(int keyCode, KeyEvent msg) {
return thread.doKeyUp(keyCode, msg);
}
/**
* Standard window-focus override. Notice focus lost so we can pause on
* focus lost. e.g. user switches to take a call.
*/
@Override
public void onWindowFocusChanged(boolean hasWindowFocus) {
if (!hasWindowFocus) thread.pause();
}
/**
* Installs a pointer to the text view used for messages.
*/
public void setTextView(TextView textView) {
mStatusText = textView;
}
/* Callback invoked when the surface dimensions change. */
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
thread.setSurfaceSize(width, height);
}
/*
* Callback invoked when the Surface has been created and is ready to be
* used.
*/
public void surfaceCreated(SurfaceHolder holder) {
// start the thread here so that we don't busy-wait in run()
// waiting for the surface to be created
thread.setRunning(true);
thread.start();
}
/*
* Callback invoked when the Surface has been destroyed and must no longer
* be touched. WARNING: after this method returns, the Surface/Canvas must
* never be touched again!
*/
public void surfaceDestroyed(SurfaceHolder holder) {
// we have to tell thread to shut down & wait for it to finish, or else
// it might touch the Surface after we return and explode
boolean retry = true;
thread.setRunning(false);
while (retry) {
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
}
}
}
}
/**
* This is a simple LunarLander activity that houses a single LunarView. It
* demonstrates...
* <ul>
* <li>animating by calling invalidate() from draw()
* <li>loading and drawing resources
* <li>handling onPause() in an animation
* </ul>
*/
public class LunarLander extends Activity {
private static final int MENU_EASY = 1;
private static final int MENU_HARD = 2;
private static final int MENU_MEDIUM = 3;
private static final int MENU_PAUSE = 4;
private static final int MENU_RESUME = 5;
private static final int MENU_START = 6;
private static final int MENU_STOP = 7;
/** A handle to the thread that's actually running the animation. */
private LunarThread mLunarThread;
/** A handle to the View in which the game is running. */
private LunarView mLunarView;
/**
* Invoked during init to give the Activity a chance to set up its Menu.
*
* @param menu the Menu to which entries may be added
* @return true
*/
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
menu.add(0, MENU_START, 0, R.string.menu_start);
menu.add(0, MENU_STOP, 0, R.string.menu_stop);
menu.add(0, MENU_PAUSE, 0, R.string.menu_pause);
menu.add(0, MENU_RESUME, 0, R.string.menu_resume);
menu.add(0, MENU_EASY, 0, R.string.menu_easy);
menu.add(0, MENU_MEDIUM, 0, R.string.menu_medium);
menu.add(0, MENU_HARD, 0, R.string.menu_hard);
return true;
}
/**
* Invoked when the user selects an item from the Menu.
*
* @param item the Menu entry which was selected
* @return true if the Menu item was legit (and we consumed it), false
* otherwise
*/
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case MENU_START:
mLunarThread.doStart();
return true;
case MENU_STOP:
mLunarThread.setState(LunarThread.STATE_LOSE,
getText(R.string.message_stopped));
return true;
case MENU_PAUSE:
mLunarThread.pause();
return true;
case MENU_RESUME:
mLunarThread.unpause();
return true;
case MENU_EASY:
mLunarThread.setDifficulty(LunarThread.DIFFICULTY_EASY);
return true;
case MENU_MEDIUM:
mLunarThread.setDifficulty(LunarThread.DIFFICULTY_MEDIUM);
return true;
case MENU_HARD:
mLunarThread.setDifficulty(LunarThread.DIFFICULTY_HARD);
return true;
}
return false;
}
/**
* Invoked when the Activity is created.
*
* @param savedInstanceState a Bundle containing state saved from a previous
* execution, or null if this is a new execution
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// tell system to use the layout defined in our XML file
setContentView(R.layout.lunar_layout);
// get handles to the LunarView from XML, and its LunarThread
mLunarView = (LunarView) findViewById(R.id.lunar);
mLunarThread = mLunarView.getThread();
// give the LunarView a handle to the TextView used for messages
mLunarView.setTextView((TextView) findViewById(R.id.text));
if (savedInstanceState == null) {
// we were just launched: set up a new game
mLunarThread.setState(LunarThread.STATE_READY);
Log.w(this.getClass().getName(), "SIS is null");
} else {
// we are being restored: resume a previous game
mLunarThread.restoreState(savedInstanceState);
Log.w(this.getClass().getName(), "SIS is nonnull");
}
}
/**
* Invoked when the Activity loses user focus.
*/
@Override
protected void onPause() {
super.onPause();
mLunarView.getThread().pause(); // pause game when Activity pauses
}
/**
* Notification that something is about to happen, to give the Activity a
* chance to save state.
*
* @param outState a Bundle into which this Activity should save its state
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
// just have the View's thread save its state into our Bundle
super.onSaveInstanceState(outState);
mLunarThread.saveState(outState);
Log.w(this.getClass().getName(), "SIS called");
}
}
//
//res\layout\lunar_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2007 The Android Open Source Project
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.example.android.lunarlander.LunarView
android:id="@+id/lunar"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="@+id/text"
android:text="@string/lunar_layout_text_text"
android:visibility="visible"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:gravity="center_horizontal"
android:textColor="#88ffffff"
android:textSize="24sp"/>
</RelativeLayout>
</FrameLayout>
//
//res\values\strings.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2007 The Android Open Source Project
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<resources>
<string name="app_name">Lunar Lander</string>
<string name="menu_start">Start</string>
<string name="menu_stop">Stop</string>
<string name="menu_pause">Pause</string>
<string name="menu_resume">Resume</string>
<string name="menu_easy">Easy</string>
<string name="menu_medium">Medium</string>
<string name="menu_hard">Hard</string>
<string name="mode_ready">Lunar Lander\nPress Up To Play</string>
<string name="mode_pause">Paused\nPress Up To Resume</string>
<string name="mode_lose">Game Over\nPress Up To Play</string>
<string name="mode_win_prefix">Success!\n</string>
<string name="mode_win_suffix">in a row\nPress Up to Play</string>
<string name="message_stopped">Stopped</string>
<string name="message_off_pad">Off Landing Pad</string>
<string name="message_too_fast">Too Fast</string>
<string name="message_bad_angle">Bad Angle</string>
<string name="lunar_layout_text_text"></string>
</resources>
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