Question

我正在尝试创建一个AlertDialog，当我在listview中点击一个项目时会打开它。但是，AlertDialog的构造函数需要一个上下文，但“this”将不起作用，因为它指向匿名函数。我尝试了“getApplicationContext（）”和“getBaseContext（）”，但是应用程序崩溃了。

有什么想法吗？

    // Open stored preferences page
    SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);

    // Load stored data key/value pairs
    Map<String, String> savedData = (Map<String, String>) settings.getAll();

    // Populate the list view in the activity with the stored data keys
    ListView lSavedData = (ListView) findViewById(R.id.lDataList);

    ArrayAdapter arrAdap = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, savedData.keySet().toArray(new String[0]) );
    lSavedData.setAdapter( arrAdap );

    lSavedData.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
            // Prepare a function selection menu for when the user selects a data item 
            AlertDialog.Builder alertBuilder = new AlertDialog.Builder( this );

            alertBuilder.setTitle("What would you like to do?");

            final CharSequence[] dialogOptions =  {"Load", "Delete"};

            alertBuilder.setItems( dialogOptions, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int item) {
                    //Toast.makeText(getApplicationContext(), dialogOptions[item], Toast.LENGTH_SHORT).show();
                }
            });

            AlertDialog functionDialog = alertBuilder.create();

            functionDialog.show();
            Toast.makeText(getApplicationContext(), "Loaded " + ((TextView) arg1).getText() + " data", Toast.LENGTH_SHORT).show();

        }
    });
}

Answer 1

使用YourActivityClassName.this，这应该有效。

Answer 2

如果在活动中创建对话框，则总是获得该活动的上下文。例如：在Activity A.with Context参数中创建对话框，您只需要设置A.his。：）

Android AlertDialog里面有一个匿名函数

2 个答案: