我有一个有 5 个选项卡的选项卡视图。每个选项卡都是一个活动。在一个选项卡中,它正在打开一个新活动,该活动打开一个警报。直到现在一切正常。
我的问题是当我从(后退按钮按下)返回时,它正在调用它的父活动的 onBackPressed 子活动,所以我正在检查活动名称getLocalActivityManager().getCurrentActivity().toString()
,当我从子活动按下后退按钮时它也可以工作,它检查活动名称使用getLocalActivityManager().getCurrentActivity().toString()
.
但是当我从我的父活动中按下返回按钮时,它会给出 NullPointer 异常。getLocalActivityManager().getCurrentActivity().toString()
从父活动调用时可能无法正常工作
LogCat 错误
家长活动
public class ProgressActivity extends ActivityGroup
{
private ArrayList<View> history;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.progress_tabview);
this.history = new ArrayList<View>();
}
public void showProgress(View v)
{
Intent intMyProg = new Intent(this,ShowProgress.class);
//intMyProg.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
//startActivity(intMyProg);
//This will help to open a new activity within existing TabView
//Need to extend ActivityGroup
//Need to declare "private ArrayList<View> history;"
//Need to Define "this.history = new ArrayList<View>();" within onCreate
View MyView = getLocalActivityManager()
.startActivity("MyIntent", intMyProg
.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP))
.getDecorView();
replaceView(MyView);
}
public void replaceView(View v)
{
history.add(v);
setContentView(v);
}
//@Override
public void onBackPressed()
{
String activityName = getLocalActivityManager().getCurrentActivity().toString();
if(activityName.contains("ShowProgress"))
{
getCurrentActivity().onBackPressed();
}
else
{
Toast.makeText(getApplicationContext(), "Back button from parent Activity", Toast.LENGTH_SHORT).show();
//finish();
}
}
}
儿童活动
public class ShowProgress extends ActivityGroup
{
private ArrayList<View> history;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.progress);
this.history = new ArrayList<View>();
AlertDialog alertDialog = new AlertDialog.Builder(ShowProgress.this.getParent()).create();
alertDialog.setTitle("Hello ...");
alertDialog.setMessage("Hello world this is Anirban !");
alertDialog.setIcon(R.drawable.tick);
alertDialog.setButton("OK", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
//Toast.makeText(getApplicationContext(), "You clicked on OK", Toast.LENGTH_SHORT).show();
}
});
alertDialog.show();
}
//@Override
public void onBackPressed()
{
Intent intMyProg = new Intent(this,ProgressActivity.class);
View MyView = getLocalActivityManager()
.startActivity("MyIntent", intMyProg
.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP))
.getDecorView();
replaceView(MyView);
}
public void replaceView(View v)
{
history.add(v);
setContentView(v);
}
}