我想要做的是每次点击“添加”按钮，都会通过列表视图将新单词添加到“测试”类中。到目前为止我所做的只会在textview中添加一个单词。但我想要的是，只要点击添加按钮，就会在列表视图中添加一个新单词。我怎么做？这是我的代码：
public class MainActivity extends Activity {
private EditText mainedit1;
private TextView maintext1;
private Button mainadd1;
private Button maindone1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
maindone1=(Button) findViewById(R.id.maindone);
mainedit1=(EditText)findViewById(R.id.mainedit1);
maintext1=(TextView)findViewById(R.id.maintext1);
mainadd1=(Button)findViewById(R.id.mainadd);
mainadd1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String test1 = mainedit1.getText().toString();
getSharedPreferences("my_prefs", Context.MODE_PRIVATE).edit().putString("word", test1).commit();
Toast.makeText(getApplicationContext(),"Word added",Toast.LENGTH_SHORT).show();
mainedit1.setText(null);
}
});
maindone1.setOnClickListener( new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,test.class);
startActivity(intent);
}
});
}
}
测试类：
public class test extends Activity {
TextView testtext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fortest);
testtext=(TextView)findViewById(R.id.testtext);
getSharedPreferences("my_prefs", Context.MODE_PRIVATE).getString("word", null);
String Word1 = getSharedPreferences("my_prefs",MODE_PRIVATE).getString("word",null).toString();
testtext.setText(Word1);
}
}
如果您知道，请通过尝试代码告诉我如何操作。
答案 0 :(得分：1)
每次单击按钮时，您似乎都会覆盖密钥："word"下的内容。您应该获取当前值，使用新单词更新它，然后添加。
替换：
getSharedPreferences("my_prefs", Context.MODE_PRIVATE).edit().putString("word", test1).commit();
使用：
String currentString = etSharedPreferences("my_prefs", Context.MODE_PRIVATE).getString("word", "");
getSharedPreferences("my_prefs", Context.MODE_PRIVATE).edit().putString("word", currentString + ", "+test1).commit();
请将内容从第二个侦听器移到第一个侦听器并删除第二个侦听器。
答案 1 :(得分：0)
您应该使用片段来保存列表视图。让你的活动保持这个片段。这样您就不会尝试将所有数据从一个活动传递到下一个活动，您只需将其添加到显示它的同一活动中即可。
所以你最终会得到一个像以下一样的MainActivity：
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new WidgetFragment())
.commit();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
片段类：
public class WidgetFragment extends Fragment {
private ArrayAdapter<String> widgetAdapter;
public WidgetFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Add this line in order for this fragment to handle menu events.
setHasOptionsMenu(true);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.widgetfragment, menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_refresh) {
FetchWidgetData widgetTask = new FetchWidgetData();
widgetTask.execute("50131");
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Create some dummy data for the ListView. Here's a sample weekly forecast
String[] data = {
"Dummy Data",
"Just an Example",
"Delete at anytime",
"Project 4",
"Project 5",
"Filler Data",
};
List<String> listData = new ArrayList<String>(Arrays.asList(data));
// Now that we have some dummy forecast data, create an ArrayAdapter.
// The ArrayAdapter will take data from a source (like our dummy forecast) and
// use it to populate the ListView it's attached to.
widgetAdapter =
new ArrayAdapter<String>(
getActivity(), // The current context (this activity)
R.layout.list_item_widget, // The name of the layout ID.
R.id.list_item_widget_textview, // The ID of the textview to populate.
listData);
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
// Get a reference to the ListView, and attach this adapter to it.
ListView listView = (ListView) rootView.findViewById(R.id.listview_widget);
listView.setAdapter(widgetAdapter);
//!!!You can add your button click listener here. And put the following line inside it to add data to your list adapter!!!
widgetAdapter.add("whatever whatever whatever"); //appends to end of list
widgetAdapter.clear(); //to reset/clear the whole thing.
widgetAdapter.remove(widgetAdapter.getItem(index); //removes the desired object. Note - remove takes object not an index.
return rootView;
}
}
编辑：键列表查看步骤。
1）创建对列表视图所在的根视图的引用
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
2）创建一个适配器来保存数据。
widgetAdapter =
new ArrayAdapter<String>(
getActivity(), // The current context (this activity)
R.layout.list_item_widget, // The name of the layout ID.
R.id.list_item_widget_textview, // The ID of the textview to populate.
new ArrayList<String>);
3）创建对listview本身的引用
ListView listView = (ListView) rootView.findViewById(R.id.listview_widget);
4）设置listview适配器
ListView.setAdapter(widgetAdapter);
5）将数据添加到适配器
widgetAdapter.add("Whatever");
编辑：添加到Main Activity类的示例静态方法，假设您已将列表适配器声明为静态类变量，
public static void addWordToList(String word){
listAdapter.add(word); //LIST ADAPTER MUST BE STATIC OR THERE MAY BE NO INSTANCE OF IT
}
}
然后你可以通过
从测试活动中调用它MainActivity.addWordToList("Whatever word you want to add");