在Android中膨胀布局

Question

我正在尝试制作一个使用RecyclerView的应用程序，以显示从项目数组中获得的项目列表。一切似乎都很好，除非我尝试在手机（Lenovo K5 Note，Android 6.0）上运行该应用程序，但该应用程序立即崩溃。我得到的错误是：

两个错误都在Adapter类中，我已将其标记为。

08-15 21:11:37.771 3163-3163/com.example.mayankthakur.reminderapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.mayankthakur.reminderapp, PID: 3163
android.content.res.Resources$NotFoundException: Resource ID #0x0
    at android.content.res.Resources.getValue(Resources.java:1552)
    at android.content.res.Resources.loadXmlResourceParser(Resources.java:3020)
    at android.content.res.Resources.getLayout(Resources.java:1330)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:421)
    at com.example.mayankthakur.reminderapp.MyAdapter.onCreateViewHolder(MyAdapter.java:36)
    at com.example.mayankthakur.reminderapp.MyAdapter.onCreateViewHolder(MyAdapter.java:10)
    at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6685)
    at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5869)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5752)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5748)
    at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2232)
    at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1559)
    at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1519)
    at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:614)
    at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3812)
    at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3529)
    at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4082)
    at android.view.View.layout(View.java:16967)
    at android.view.ViewGroup.layout(ViewGroup.java:5584)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1189)
    at android.view.View.layout(View.java:16967)
    at android.view.ViewGroup.layout(ViewGroup.java:5584)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
    at android.view.View.layout(View.java:16967)
    at android.view.ViewGroup.layout(ViewGroup.java:5584)
    at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:443)
    at android.view.View.layout(View.java:16967)
    at android.view.ViewGroup.layout(ViewGroup.java:5584)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
    at android.view.View.layout(View.java:16967)
    at android.view.ViewGroup.layout(ViewGroup.java:5584)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:2001)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1844)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1753)
    at android.view.View.layout(View.java:16967)
    at android.view.ViewGroup.layout(ViewGroup.java:5584)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
    at com.android.internal.policy.PhoneWindow$DecorView.onLayout(PhoneWindow.java:2769)
    at android.view.View.layout(View.java:16967)
    at android.view.ViewGroup.layout(ViewGroup.java:5584)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2547)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2250)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1321)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6732)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:894)
    at android.view.Choreographer.doCallbacks(Choreographer.java:696)
    at android.view.Choreographer.doFrame(Choreographer.java:631)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:880)
    at android.os.Handler.handleCallback(Handler.java:815)
    at android.os.Handler.dispatchMessage(Handler.java:104)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:5740)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCall

商品类：

public class Item extends AppCompatActivity implements View.OnClickListener{

public Item[] data;

EditText tName;
EditText difficulty;
Button addResource;

private String topicName;
private int time;
private int adifficulty;
private int size;



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

    size = data.length;
    tName = findViewById(R.id.editText);
    difficulty = findViewById(R.id.editText2);
    addResource = findViewById(R.id.button);
    addResource.setOnClickListener(this);


    MainActivity.method(data);

   }

public Item (String name, int difficulty){
    this.topicName = name;
    this.adifficulty = difficulty;

}

public String getTopicName() {
    return topicName;
}

public int getTime(){
    return time;
}

public int getDifficulty(){
    return adifficulty;
}

@Override
public void onClick(View view) {
    topicName = tName.getText().toString();
    String i = difficulty.getText().toString();
    adifficulty = Integer.parseInt(i);
    Item thing = new Item (topicName, adifficulty);
    data[size + 1 ] = thing;



}

}

MainActivity：

 public class MainActivity extends AppCompatActivity implements View.OnClickListener{

static Item thing = new Item("hello", 34);1 // assigning a random value to the dataset to make sure i dont get any nullpointerexceptions

static Item[] theDataset = {thing};
public static void method (Item[] data){
    theDataset = data;
}

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

    FloatingActionButton nBut = (FloatingActionButton) findViewById(R.id.fab);
    nBut.setOnClickListener(this);

    RecyclerView mRecyclerView = (RecyclerView) findViewById(R.id.mRecyclerView);

    mRecyclerView.setHasFixedSize(true);

    LinearLayoutManager mLayoutManager = new LinearLayoutManager(this);
    mRecyclerView.setLayoutManager(mLayoutManager);

    MyAdapter mAdapter = new MyAdapter(theDataset);
    mRecyclerView.setAdapter(mAdapter);

}

@Override
public void onClick(View view) {

    switch (view.getId()) {

        case com.example.mayankthakur.reminderapp.R.id.fab:
            Intent i = new Intent(this, Item.class );
            startActivity(i);

            break;

        default:
            break;
    }


}

}

AdapterClass：

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> { //ERROR
private Item [] mDataset;


public class ViewHolder extends RecyclerView.ViewHolder {
    private TextView mTextView;

    public ViewHolder(final View v) {
        super(v);
        mTextView = (TextView) v.findViewById(R.id.textView);
    }
}

// Provide a reference to th    e views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder

// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(Item[] myDataset) {
    mDataset = myDataset;
}

// Create new views (invoked by the layout manager)
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    // create a new view
    final View view = LayoutInflater.from(parent.getContext()).inflate(viewType, parent, false); //ERROR
    return new ViewHolder(view);
}

// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    // - get element from your dataset at this position
    // - replace the contents of the view with that element
    holder.mTextView.setText(mDataset[position].getTopicName());

}

// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
    return mDataset.length;
}

}

任何有关此问题的帮助将不胜感激！

Answer 1

尝试一下：

LayoutInflater.from(parent.getContext()).inflate(R.layout.your_item.xml, parent, false);

Answer 2

问题出在viewType 应该是您的布局xml

LayoutInflater.from(parent.getContext()).inflate(R.layout.your_item.xml, parent, false); 

Answer 3

您看到的Exception是由此行引起的

final View view = LayoutInflater.from(parent.getContext()).inflate(viewType, parent, false);

在这里，您从onCreateViewHolder()传入参数 viewType 。因为您没有在getItemViewType()中覆盖RecyclerView.Adapter，所以它将始终为0。

  

此方法的默认实现返回0，并假设适配器具有单一视图类型。

（引自documentation on RecyclerView.Adapter）

但是inflate()此时需要一个有效的布局ID，类似于R.layout.list_row，其中可以在res/layout文件夹中找到list_row.xml。 0永远不是有效的资源标识符，因此您的应用程序崩溃了

注意：仅在需要根据当前位置的数据为不同的布局充气时（运行时将调用getItemViewType(int position)以确定正确的值）时，才需要评估 viewType < / p>