我正在学习结构并使用结构mvvm制作应用程序。mvvmdata binding
现在，我想做的是，我想从 sharedpreference 中获取一个用户，如果我成功获取了一个用户，我会将 usr 的名称设置为edittext1. 在这种情况下，我想请求关注 edittext2。
如何使用数据绑定来实现？（以这样的方式，我不必使用活动。这项工作应该只使用视图模型和 xml 来完成。）
我已经尝试过使用以下方式。
开始游戏视图模型
public class StartGameViewModel extends ViewModel {
public static String TAG="StartGameViewModel";
private Preference<User> preference;
public ObservableField<String> player1Name=new ObservableField<>("");
public ObservableField<String> player2Name=new ObservableField<>("");
public ObservableBoolean shouldRequestFocus=new ObservableBoolean(false);
StartGameViewModel(Preference preference){
this.preference=preference;
}
public void getPreference() {
preference.get(Constants.CURRENT_USER,User.class)
.subscribe(new Observer<User>() {
@Override
public void onSubscribe(Disposable d) {
}
@Override
public void onNext(User user) {
player1Name.set(user.name);
shouldRequestFocus.set(true);
}
@Override
public void onError(Throwable e) {
Log.i(TAG,"user is logged out");
}
@Override
public void onComplete() {
Log.i(TAG,"Completed Preference");
}
});
}
}
activity_start_game.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".view.StartGameActivity">
<data>
<variable
name="startGameViewModel"
type="com.sevenbits.android.mvvmsample.viewmodel.StartGameViewModel" />
</data>
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/splash_bg">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Enter Players Name"
android:textSize="24sp"
android:textColor="@color/white"
app:layout_constraintVertical_bias="0.75"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintBottom_toTopOf="@+id/input_layout"
app:layout_constraintTop_toTopOf="parent"
/>
<LinearLayout
android:id="@+id/input_layout"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginLeft="40dp"
android:layout_marginRight="40dp"
android:background="@color/white"
android:elevation="20dp"
android:orientation="vertical"
android:paddingBottom="40dp"
android:paddingLeft="20dp"
android:paddingRight="20dp"
android:paddingTop="40dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.45"
tools:layout_editor_absoluteX="8dp">
<android.support.design.widget.TextInputLayout
android:id="@+id/til_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp">
<android.support.design.widget.TextInputEditText
android:id="@+id/et_player1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Player1"
android:text="@{startGameViewModel.player1Name}"
app:addTextChangedListener="@{startGameViewModel.Player1Watcher}" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:id="@+id/til_password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp">
<android.support.design.widget.TextInputEditText
android:id="@+id/et_player2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Player2"
android:text="@{startGameViewModel.player2Name}"
app:addTextChangedListener="@{startGameViewModel.Player2Watcher}" />
</android.support.design.widget.TextInputLayout>
</LinearLayout>
<Button
android:id="@+id/start_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_button"
android:elevation="20dp"
android:gravity="center"
android:paddingBottom="20dp"
android:paddingEnd="40dp"
android:paddingStart="40dp"
android:paddingTop="20dp"
android:text="Start"
android:textAllCaps="false"
android:textColor="@color/white"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@+id/input_layout" />
</android.support.constraint.ConstraintLayout>
</layout>
开始游戏活动：
public class StartGameActivity extends AppCompatActivity {
ActivityStartGameBinding activityStartGameBinding;
StartGameViewModel startGameViewModel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initDataBinding();
setStartGameListener();
}
private void initDataBinding() {
activityStartGameBinding = DataBindingUtil.setContentView(this, R.layout.activity_start_game);
StartGameViewModelFactory startGameViewModelFactory= Injection.provideStartGameViewModelFactory(this);
startGameViewModel = ViewModelProviders.of(this,startGameViewModelFactory).get(StartGameViewModel.class);
activityStartGameBinding.setStartGameViewModel(startGameViewModel);
startGameViewModel.getPreference();
if(startGameViewModel.shouldRequestFocus.get())
findViewById(R.id.et_player2).requestFocus();
}
private void setStartGameListener() {
findViewById(R.id.start_button).setOnClickListener(v -> {
Intent intent=new Intent(StartGameActivity.this,GameActivity.class);
intent.putExtra(Constants.PLAYER1_NAME,startGameViewModel.player1Name.get());
intent.putExtra(Constants.PLAYER2_NAME,startGameViewModel.player2Name.get());
startActivity(intent);
});
}
}