如何显示对话框以确认用户希望退出 Android Activity？
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How to show a dialog to confirm that the user wishes to exit an Android Activity?
提问by Peter A
I've been trying to show a "Do you want to exit?" type of dialog when the user attempts to exit an Activity.
我一直在尝试显示“您想退出吗？” 用户尝试退出活动时的对话框类型。
However I can't find the appropriate API hooks. Activity.onUserLeaveHint()initially looked promising, but I can't find a way to stop the Activity from finishing.
但是我找不到合适的 API 钩子。 Activity.onUserLeaveHint()最初看起来很有希望，但我找不到阻止活动完成的方法。
回答by jax
In Android 2.0+ this would look like:
在 Android 2.0+ 中，这看起来像：
@Override
public void onBackPressed() {
new AlertDialog.Builder(this)
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("Closing Activity")
.setMessage("Are you sure you want to close this activity?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
})
.setNegativeButton("No", null)
.show();
}
In earlier versions it would look like:
在早期版本中，它看起来像：
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
//Handle the back button
if(keyCode == KeyEvent.KEYCODE_BACK) {
//Ask the user if they want to quit
new AlertDialog.Builder(this)
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle(R.string.quit)
.setMessage(R.string.really_quit)
.setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//Stop the activity
YourClass.this.finish();
}
})
.setNegativeButton(R.string.no, null)
.show();
return true;
}
else {
return super.onKeyDown(keyCode, event);
}
}
回答by Chanakya Vadla
@Override
public void onBackPressed() {
new AlertDialog.Builder(this)
.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
ExampleActivity.super.onBackPressed();
}
})
.setNegativeButton("No", null)
.show();
}
回答by suraj jain
Have modified @user919216 code .. and made it compatible with WebView
已修改@user919216 代码.. 并使其与 WebView 兼容
@Override
public void onBackPressed() {
if (webview.canGoBack()) {
webview.goBack();
}
else
{
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
}
回答by Toni Gamez
I'd prefer to exit with double tap on the back button than with an exit Dialog.
我更喜欢双击后退按钮退出，而不是退出对话框。
In this solution, it show a toast when go back for the first time, warning that another back press will close the App. In this example less than 4 seconds.
在这个解决方案中，它在第一次返回时显示一个祝酒词，警告再次按下将关闭应用程序。在这个例子中不到 4 秒。
private Toast toast;
private long lastBackPressTime = 0;
@Override
public void onBackPressed() {
if (this.lastBackPressTime < System.currentTimeMillis() - 4000) {
toast = Toast.makeText(this, "Press back again to close this app", 4000);
toast.show();
this.lastBackPressTime = System.currentTimeMillis();
} else {
if (toast != null) {
toast.cancel();
}
super.onBackPressed();
}
}
Token from: http://www.androiduipatterns.com/2011/03/back-button-behavior.html
令牌来自：http: //www.androiduipatterns.com/2011/03/back-button-behavior.html
回答by GLee
If you are not sure if the call to "back" will exit the app, or will take the user to another activity, you can wrap the above answers in a check, isTaskRoot(). This can happen if your main activity can be added to the back stack multiple times, or if you are manipulating your back stack history.
如果您不确定对“back”的调用是否会退出应用程序，或者是否会将用户带到另一个活动，您可以将上述答案包含在检查中，isTaskRoot()。如果您的主要活动可以多次添加到后台堆栈，或者您正在操纵后台堆栈历史记录，就会发生这种情况。
if(isTaskRoot()) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
YourActivity.super.onBackPressed;
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
} else {
super.onBackPressed();
}
回答by vasiljevski
Using Lambda:
使用 Lambda：
new AlertDialog.Builder(this).setMessage(getString(R.string.exit_msg))
.setTitle(getString(R.string.info))
.setPositiveButton(getString(R.string.yes), (arg0, arg1) -> {
moveTaskToBack(true);
finish();
})
.setNegativeButton(getString(R.string.no), (arg0, arg1) -> {
})
.show();
You also need to set level language to support java 8 in your gradle.build:
您还需要在 gradle.build 中设置级别语言以支持 java 8：
compileOptions {
targetCompatibility 1.8
sourceCompatibility 1.8
}
回答by u445908
in China, most App will confirm the exit by "click twice":
在中国，大多数App会通过“点击两次”确认退出：
boolean doubleBackToExitPressedOnce = false;
@Override
public void onBackPressed() {
if (doubleBackToExitPressedOnce) {
super.onBackPressed();
return;
}
this.doubleBackToExitPressedOnce = true;
Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
doubleBackToExitPressedOnce=false;
}
}, 2000);
}
回答by Anjali-Systematix
First remove super.onBackPressed();from onbackPressed()method than and below code:
首先super.onBackPressed();从onbackPressed()方法中删除比和下面的代码：
@Override
public void onBackPressed() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
MyActivity.this.finish();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
回答by marioosh
I like a @GLee approach and using it with fragment like below.
我喜欢 @GLee 方法并将其与如下所示的片段一起使用。
@Override
public void onBackPressed() {
if(isTaskRoot()) {
new ExitDialogFragment().show(getSupportFragmentManager(), null);
} else {
super.onBackPressed();
}
}
Dialog using Fragment:
使用 Fragment 的对话框：
public class ExitDialogFragment extends DialogFragment {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return new AlertDialog.Builder(getActivity())
.setTitle(R.string.exit_question)
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
getActivity().finish();
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
getDialog().cancel();
}
})
.create();
}
}
回答by Mohit Hooda
Just put this code in your first activity
@Override
public void onBackPressed() {
if (drawerLayout.isDrawerOpen(GravityCompat.END)) {
drawerLayout.closeDrawer(GravityCompat.END);
}
else {
// if your using fragment then you can do this way
int fragments = getSupportFragmentManager().getBackStackEntryCount();
if (fragments == 1) {
new AlertDialog.Builder(this)
.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
}
})
.setNegativeButton("No", null)
.show();
} else {
if (getFragmentManager().getBackStackEntryCount() > 1) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
}
}
