我正在制作一个简单的日志应用程序,让用户输入时间和备注,然后在ListView
的专用活动(MainActivty
)中显示输入的数据。时间和数据输入一个单独的活动(AddTimeActivity
)与两个EditText
和输入MainActivity
通过适配器(TimeTrackerAdapter
)点击保存按钮时传递。或者,当用户改变主意时可以按下取消按钮。可以通过操作栏默认菜单中的添加按钮访问AddTimeActivity
。现在我已经添加了一个删除按钮(它工作正常),并且在列表中的每一行都添加了一个编辑按钮。现在的问题是:如何添加编辑功能而不用专门编辑新的活动。换句话说,我怎样才能让AddTimeActivity
在编辑和添加的同时工作,我如何让我的应用程序知道用户点击了添加按钮,然后用空EditText
开始AddTimeActivity
,或者用户点击了编辑按钮,并将要编辑的数据传递到AddTimeActivity
,并将它们显示在EditText
中,并将编辑后的数据保存在同一条目中?对不起,没有显示任何尝试,但我实际上对这个问题无能为力。在列表视图中编辑条目
MainActivity.java
public class MainActivity extends AppCompatActivity {
public TimeTrackerAdapter timeTrackerAdapter;
public int TIME_ENTRY_REQUEST_CODE = 1;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listView = (ListView) findViewById(R.id.time_list);
timeTrackerAdapter = new TimeTrackerAdapter();
listView.setAdapter(timeTrackerAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
super.onCreateOptionsMenu(menu);
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.menu_main, menu);
return true;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == TIME_ENTRY_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
Bundle bundle = data.getExtras();
String time = bundle.getString("time");
String note = bundle.getString("note");
TimeRecord timeRecord = new TimeRecord(time, note);
timeTrackerAdapter.addTimeRecord(timeRecord);
timeTrackerAdapter.notifyDataSetChanged();
}
}
}
@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.add_time_item) {
Intent intent = new Intent(getApplicationContext(), AddTimeActivity.class);
startActivityForResult(intent, TIME_ENTRY_REQUEST_CODE);
return true;
}
else if (id == R.id.about) {
Intent aboutIntent = new Intent(getApplicationContext(), AboutScreen.class);
startActivity(aboutIntent);
}
return super.onOptionsItemSelected(item);
}
}
的AddTimeActivity
,onSave
和onCancel
是按钮的方法:
public class AddTimeActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_time);
}
public void onCancel(View view) {
finish();
}
public void onSave(View view) {
Intent intent = new Intent(AddTimeActivity.this, MainActivity.class);
EditText timeEditText = (EditText) findViewById(R.id.Time_Edit_Text);
String time = timeEditText.getText().toString();
EditText noteEditText = (EditText) findViewById(R.id.Note_Edit_Text);
String note = noteEditText.getText().toString();
intent.putExtra("time", time);
intent.putExtra("note", note);
this.setResult(RESULT_OK, intent);
finish();
}
}
TimeTrackerAdapter.java:
public class TimeTrackerAdapter extends BaseAdapter {
public ArrayList<TimeRecord> times = new ArrayList<TimeRecord>();
@Override
public int getCount() {
return times.size();
}
public TimeTrackerAdapter() {
times.add(new TimeRecord("12:30", "this is the best"));
times.add(new TimeRecord("2:30", "I need this"));
}
@Override
public Object getItem(int position) {
return times.get(position);
}
public void addTimeRecord(TimeRecord timeRecord) {
times.add(timeRecord);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View view, ViewGroup parent) {
if (view == null) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
view = inflater.inflate(R.layout.menu_layout, parent, false);
}
TextView timeView = (TextView) view.findViewById(R.id.time_textView);
TextView noteView = (TextView) view.findViewById(R.id.note_TextView);
Button deleteButton = (Button) view.findViewById(R.id.delete_entry);
deleteButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
times.remove(position);
notifyDataSetChanged();
}
});
TimeRecord time = times.get(position);
timeView.setText(time.getTime());
noteView.setText(time.getNote());
return view;
}
}
使用'ViewHolder'来管理你的列表视图适配器,请参阅本教程:https://www.codeofaninja.com/2013/09/android-viewholder-pattern-example.html – AsfK