Android 再按一次返回，即退出应用，实现工具类

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/aaa1050070637/article/details/82345655

我们在使用APP的时候，会遇到这样一种情况，就是双击返回，就退出应用。

为此封装了一个工具类，仅供大家参考

public class DoubleClickExitHelper {

	private final Activity mActivity;
	
	private boolean isOnKeyBacking;
	private Handler mHandler;
	private Toast mBackToast;
	
	public DoubleClickExitHelper(Activity activity) {
		mActivity = activity;
		mHandler = new Handler(Looper.getMainLooper());
	}
	
	/**
	 * Activity onKeyDown事件
	 * */
	public boolean onKeyDown(int keyCode) {
		if(keyCode != KeyEvent.KEYCODE_BACK) {
			return false;
		}
		if(isOnKeyBacking) {
			mHandler.removeCallbacks(onBackTimeRunnable);
			if(mBackToast != null){
				mBackToast.cancel();
			}
			Log.i("nnn", "isOnKeyBacking***********************");
//Activity 堆栈式管理，退出应用时，退出所有的Activity
			APPActivityManager.getAppManager().AppExit(mActivity);
			return true;
		} else {
			isOnKeyBacking = true;
			if(mBackToast == null) {
				Log.i("nnn", "null***********************");
				mBackToast = Toast.makeText(mActivity,               "再按一次，即退出应用", Toast.LENGTH_LONG);
			}
			mBackToast.show();
			mHandler.postDelayed(onBackTimeRunnable, 2000);
			return true;
		}
	}
	
	private Runnable onBackTimeRunnable = new Runnable() {
		
		@Override
		public void run() {
			isOnKeyBacking = false;
			if(mBackToast != null){
				mBackToast.cancel();
			}
		}
	};
}

调用的方法，想必大家一看便一目了然，直接在初始化对象即可。