Question

我已经开始Android开发，直到现在我没有问题，但我试图将RecyclerView插入我的布局，一切都很好没有错误，但我的RecyclerView本身没有显示。代码似乎对我来说。

这是我的代码：

MainActivity.java：

public class MainActivity extends AppCompatActivity {

private Toolbar toolbar;
private RVAdapter adapter;

private RecyclerView recyclerView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    toolbar = (Toolbar) findViewById(R.id.app_bar);
    setSupportActionBar(toolbar);

    getSupportActionBar().setDisplayShowHomeEnabled(true);
    NavigationDrawerFragment drawerFragment = (NavigationDrawerFragment) getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
    drawerFragment.setUp(R.id.fragment_navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), (Toolbar) findViewById(R.id.app_bar));

    recyclerView = (RecyclerView) findViewById(R.id.goalList);
    recyclerView.setHasFixedSize(true);
    adapter = new RVAdapter(getApplication(), getData());
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(getApplication()));

}

public static List<RVData> getData() {
    List<RVData> data = new ArrayList<>();
    String[] titles = {"Dummy1", "Dummy2", "Dummy3"};

    for (int i = 0; i < titles.length; i++) {
        RVData current = new RVData();
        current.goalTitle = titles[i];
        data.add(current);
    }
    return data;
}

public void newGoal(View view) {
    Intent intent = new Intent(MainActivity.this, NewGoal.class);
    startActivity(intent);
}

@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);
}
}

activity_main.xml：

<RelativeLayout 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"
style="@style/DefaultLayoutStyle"
tools:context=".MainActivity">

<include
    android:id="@+id/app_bar"
    layout="@layout/app_bar" />


<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    style="@style/FABStyle"
    android:onClick="newGoal"
    android:src="@drawable/ic_add"
    app:borderWidth="0dp" />

<android.support.v4.widget.DrawerLayout
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@id/app_bar">

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/goalList"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"></android.support.v7.widget.RecyclerView>
    </RelativeLayout>

    <fragment
        android:id="@+id/fragment_navigation_drawer"
        android:name="com.kellarapps.zeal.NavigationDrawerFragment"
        android:layout_width="@dimen/nav_drawer_width"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:layout="@layout/fragment_navigation_drawer"
        tools:layout="@layout/fragment_navigation_drawer" />

</android.support.v4.widget.DrawerLayout>
</RelativeLayout>

goal_row.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">

<CheckBox
    android:id="@+id/goalRowCB"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/goalRowTitle"
    android:textSize="17sp"
    android:clickable="true"
    android:layout_width="match_parent"
    android:gravity="center_horizontal"
    android:layout_height="wrap_content"
    android:textColor="@color/TextColor"
    android:text="@string/dummyTxt"/>

</LinearLayout>

RVData.java：

public class RVData {
    CheckBox checkBox;
    String goalTitle;

}

RVAdapter.java

public class RVAdapter extends RecyclerView.Adapter<RVAdapter.myViewHolder> {

List<RVData> data = Collections.emptyList();
private LayoutInflater inflater;

public RVAdapter(Context context, List<RVData> cData) {
    inflater = LayoutInflater.from(context);
    this.data = cData;
}

@Override
public myViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View view = inflater.inflate(R.layout.goal_row, viewGroup, false);
    myViewHolder holder = new myViewHolder(view);
    return holder;
}

@Override
public void onBindViewHolder(myViewHolder viewHolder, int position) {
    RVData current = data.get(position);
    viewHolder.title.setText(current.goalTitle);

}

@Override
public int getItemCount() {
    return 0;
}

class myViewHolder extends RecyclerView.ViewHolder {
    @Bind(R.id.goalRowTitle)
    TextView title;
    @Bind(R.id.goalRowCB)
    CheckBox checkBox;

    public myViewHolder(View itemView) {
        super(itemView);
        title = (TextView) itemView;
        checkBox = (CheckBox) itemView;
        }
    }
}

没有错误，但也没有RecyclerView。

Answer 1

有一点很突出，您的项目计数被硬编码为0。您应该返回该函数中的数据大小：

@Override
public int getItemCount() {
    return data.size();
}

Answer 2

你可能会在这里省去一些麻烦：

class myViewHolder extends RecyclerView.ViewHolder {
    @Bind(R.id.goalRowTitle)
    TextView title;
    @Bind(R.id.goalRowCB)
    CheckBox checkBox;

    public myViewHolder(View itemView) {
        super(itemView);
        title = (TextView) itemView;
        checkBox = (CheckBox) itemView;
    }
}

更直接的是：

class myViewHolder extends RecyclerView.ViewHolder {
    //@Bind(R.id.goalRowTitle)
    TextView title;
    //@Bind(R.id.goalRowCB)
    CheckBox checkBox;

    public myViewHolder(View itemView) {
        super(itemView);
        title = (TextView) itemView.findViewById(R.id.goalRowTitle);
        checkBox = (CheckBox) itemView.findViewById(R.id.goalRowCB);
    }
    }

将此与blackcj注意到的getCount问题相结合，您应该解决您的问题。更有可能的是，为什么你没有得到类型不匹配的原因，试图将不是TextView的视图或Checkboxes设置为那些类型......

RecyclerView无法显示没有错误

2 个答案: