我有一个活动,如果第一次启动,显示欢迎信息：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
showWelcomeMessageIfNecessary();
}
private void showWelcomeMessageIfNecessary() {
final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
final Editor edit = prefs.edit();
if (!prefs.getBoolean("welcomemessage",false)) {
edit.putBoolean("welcomemessage",true);
edit.commit();
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(R.string.messages_welcome_content).setCancelable(false).setPositiveButton(R.string.errors_ok,new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// Do nothing
}
}).setTitle(R.string.messages_welcome_title);
AlertDialog alert = builder.create();
alert.show();
}
}
这一切都很美妙,但是当我启动应用程序,并立即旋转屏幕,我得到了众所周知的泄漏窗口异常.
我该如何防止这种情况？有更好的方式来显示对话吗？当我在Fragments中的AsyncTasks中使用ProgressDialogs时也会发生这种情况.
解决方法
您需要在活动的onStop或onDestroy方法中取消对话框.例如：
private AlertDialog diag = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
diag = showWelcomeMessageIfNecessary();
if(diag != null)
diag.show();
}
private AlertDialog showWelcomeMessageIfNecessary() {
final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
final Editor edit = prefs.edit();
AlertDialog alert = null;
if (!prefs.getBoolean("welcomemessage",int id) {
// Do nothing
}
}).setTitle(R.string.messages_welcome_title);
alert = builder.create();
}
return alert;
}
@Override
protected void onStop() {
super.onStop();
if(diag != null)
diag.dismiss();
}
