android 点击返回键退出程序的方法

第一种：再按一次返回键退出程序

privatelongexitTime=0;

@Override
publicbooleanonKeyDown(intkeyCode,KeyEventevent){
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);
}
returntrue;
}
returnsuper.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);
}

第二种：点击返回键弹出确定窗口选择退出

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

.setTitle("确定退出程序么")

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

@Override

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

})

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

public void onClick(DialogInterface dialog, int whichButton) {

finish();//

}

}).show();

return true;

}
return super.dispatchKeyEvent(event);
}

android 点击返回键退出程序的方法

android 点击返回键退出程序的方法

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