Android 实现Activity后台运行

此方法其实不是主要是屏蔽Keycode_Back，让它不结束（finish()）Activity，直接显示HOME界面。

 

PackageManager pm = getPackageManager();
                              ResolveInfo homeInfo = pm.resolveActivity(new
 Intent(Intent.ACTION_MAIN)
.addCategory(Intent.CATEGORY_HOME), 0
);

		PackageManager pm = getPackageManager();
                                ResolveInfo homeInfo = pm.resolveActivity(new Intent(Intent.ACTION_MAIN)
		.addCategory(Intent.CATEGORY_HOME), 0);

 

 

public
 
boolean
 onKeyDown(
int
 keyCode, KeyEvent event) {
    if
 (keyCode == KeyEvent.KEYCODE_BACK) {
        ActivityInfo ai = homeInfo.activityInfo;
        Intent startIntent = new
 Intent(Intent.ACTION_MAIN);
        startIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        startIntent.setComponent(new
 ComponentName(ai.packageName,
                ai.name));
        startActivitySafely(startIntent);
        return
 
true
;
    } else
        return
 
super
.onKeyDown(keyCode, event);
}

	public boolean onKeyDown(int keyCode, KeyEvent event) {
		if (keyCode == KeyEvent.KEYCODE_BACK) {
			ActivityInfo ai = homeInfo.activityInfo;
			Intent startIntent = new Intent(Intent.ACTION_MAIN);
			startIntent.addCategory(Intent.CATEGORY_LAUNCHER);
			startIntent.setComponent(new ComponentName(ai.packageName,
					ai.name));
			startActivitySafely(startIntent);
			return true;
		} else
			return super.onKeyDown(keyCode, event);
	}

 

 

void
 startActivitySafely(Intent intent) {
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    try
 {
        startActivity(intent);
    } catch
 (ActivityNotFoundException e) {
        Toast.makeText(this
, R.string.unabletoopensoftware,
                Toast.LENGTH_SHORT).show();
    } catch
 (SecurityException e) {
        Toast.makeText(this
, R.string.unabletoopensoftware,
                Toast.LENGTH_SHORT).show();
        Log
                .e(
                        TAG,
                        "Launcher does not have the permission to launch "
                                + intent
                                + ". Make sure to create a MAIN intent-filter for the corresponding activity "
                                + "or use the exported attribute for this activity."
,
                        e);
    }
}