Android Open Source - SwitchTabs Main Activity

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License

The source code is released under:
Apache License
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Java Source Code

package com.normal.testdemo.activitys;
/*from  w  w  w  .j  a  v a2  s  . c  om*/
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import com.normal.testdemo.R;
import com.normal.testdemo.adapters.SectionsPagerAdapter;

import java.io.File;
import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends ActionBarActivity implements ActionBar.TabListener {
  public static Context context;
  private boolean isPressed = false; // ???????????back?
  /**
   * The {@link android.support.v4.view.PagerAdapter} that will provide
   * fragments for each of the sections. We use a {@link FragmentPagerAdapter}
   * derivative, which will keep every loaded fragment in memory. If this
   * becomes too memory intensive, it may be best to switch to a
   * {@link android.support.v4.app.FragmentStatePagerAdapter}.
   */
  SectionsPagerAdapter mSectionsPagerAdapter;

  /**
   * The {@link ViewPager} that will host the section contents.
   */
  ViewPager mViewPager;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Log.i("MainActivity","MainActivity Created");
    context = getApplicationContext();
    // Set up the action bar.
    final ActionBar actionBar = getSupportActionBar();
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Create the adapter that will return a fragment for each of the three
    // primary sections of the activity.
    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.pager);
    //??viewpager??Fragment
    mViewPager.setAdapter(mSectionsPagerAdapter);

    // When swiping between different sections, select the corresponding
    // tab. We can also use ActionBar.Tab#select() to do this if we have
    // a reference to the Tab.
    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
      @Override
      public void onPageSelected(int position) {
        actionBar.setSelectedNavigationItem(position);
      }
    });

    // For each of the sections in the app, add a tab to the action bar.
    for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
      // Create a tab with text corresponding to the page title defined by
      // the adapter. Also specify this Activity object, which implements
      // the TabListener interface, as the callback (listener) for when
      // this tab is selected.
      //??TabTitle
      actionBar.addTab(actionBar.newTab()
          .setText(mSectionsPagerAdapter.getPageTitle(i))
          .setTabListener(this));
    }
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
  }

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
    // ????????item?id?????????id?????????
    switch (item.getItemId()) {
      case R.id.action_clean_cache:
        cleanCache();
        Toast.makeText(this, R.string.clean_cache_success, Toast.LENGTH_SHORT).show();
        break;
    }
    return super.onOptionsItemSelected(item);
  }

  @Override
  public void onTabSelected(ActionBar.Tab tab,
                            FragmentTransaction fragmentTransaction) {
    // When the given tab is selected, switch to the corresponding page in
    // the ViewPager.
    mViewPager.setCurrentItem(tab.getPosition());
  }

  @Override
  public void onTabUnselected(ActionBar.Tab tab,
                              FragmentTransaction fragmentTransaction) {
  }

  @Override
  public void onTabReselected(ActionBar.Tab tab,
                              FragmentTransaction fragmentTransaction) {
  }

  // ????
  private void cleanCache() {
    File file = getCacheDir();
    File[] subFiles = file.listFiles();
    for (File f : subFiles) {
      f.delete();
    }
  }

  // ???????????????
  @Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
    // ?????????
    if (keyCode == KeyEvent.KEYCODE_BACK) {
      exitByDoubleBack();
    }
    return false;
  }

  // ???????????
  private void exitByDoubleBack() {
    Timer time = null;
    if (isPressed == false) {
      isPressed = true;
      // ??Toast???
      Toast.makeText(this, R.string.note, Toast.LENGTH_LONG).show();
      time = new Timer();
      // ??????????????????????
      time.schedule(new TimerTask() {
        @Override
        public void run() {
          isPressed = false;
        }
      }, 2000);
    } else {
      // ????????????
      android.os.Process.killProcess(android.os.Process.myPid());
      System.exit(0);
    }
  }
}
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