android 點擊返回鍵退出程序的方法

android 點擊返回鍵退出程序的方法

第一種： 再按一次返回鍵退出程序

private long exitTime = 0;

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN){
if((System.currentTimeMillis()-exitTime) > 2000){
Toast.makeText(getApplicationContext(), "再按一次退出程序", Toast.LENGTH_SHORT).show();
exitTime = System.currentTimeMillis();
} else {
finish();
System.exit(0);
}
return true;
}
return super.onKeyDown(keyCode, event);
}

或者

private long exitTime = 0;


@Override
public boolean dispatchKeyEvent(KeyEvent event) {
if (event.getKeyCode() == KeyEvent.KEYCODE_BACK
&& event.getAction() == KeyEvent.ACTION_DOWN
&& event.getRepeatCount() == 0) {
if((System.currentTimeMillis()-exitTime) > 2000){
Toast.makeText(getApplicationContext(), "再按一次退出程序！", Toast.LENGTH_SHORT).show();
exitTime = System.currentTimeMillis();
} else {
finish();
System.exit(0);
}
return true;
}

return super.dispatchKeyEvent(event);
}

第二種：點擊返回鍵彈出確定窗口 選擇退出

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
if (event.getKeyCode() == KeyEvent.KEYCODE_BACK
&& event.getAction() == KeyEvent.ACTION_DOWN
&& event.getRepeatCount() == 0) {
//具體的操作代碼
new AlertDialog.Builder(this)


.setTitle("確定退出程序麼")



.setNegativeButton("取消", new DialogInterface.OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {
}

})

.setPositiveButton("確定", new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int whichButton) {

finish();//

}

}).show();

return true;

}
return super.dispatchKeyEvent(event);
}