Question

我有一个完全适用于API 15-19的应用程序，我在将其迁移到AppCompat时遇到了问题：当我将MainActivity extends FragmentActivity更改为MainActivity extends AppCompatActivity时，编译失败（我也会更新所有相应的库并将getFragmentManager()替换为getSupportFragmentManager()）。试图找出导致这个错误的原因我发现当ListView的适配器填充其中一个项目按钮（即第一个按钮id="@+id/time_field"）时会发生这种情况：

listitem_task.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/item_layout"
    android:paddingBottom="5dp">

    <Button
        android:id="@+id/time_field"
        android:layout_width="115dp"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginRight="5dp"
        android:layout_marginEnd="5dp"
        android:textColor="@color/black_col"
        android:paddingLeft="2dp"
        android:paddingRight="2dp"
        android:singleLine="true"
        android:textSize="18sp"
        android:longClickable="false"
        android:enabled="true"
        android:focusable="false"
        android:clickable="false"
        android:focusableInTouchMode="false"
        android:layout_alignParentBottom="false" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/task_field"
        android:layout_alignParentTop="true"
        android:layout_toRightOf="@+id/time_field"
        android:layout_toEndOf="@+id/time_field"
        android:textColor="@color/black_col"
        android:gravity="start|center"
        android:paddingLeft="10dp"
        android:clickable="false"
        android:enabled="true"
        android:focusable="false"
        android:focusableInTouchMode="false"
        android:longClickable="false"
        android:paddingRight="10dp"
        android:maxLines="2" />
</RelativeLayout>

因此，当我在ListView 适配器（// FORMATTING TIME-FIELD:之后的行中）注释掉负责格式化此按钮的行时，这个错误不会发生：

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;

import java.util.ArrayList;

public class TaskAdapter extends BaseAdapter {
    private ArrayList<Task> taskList;
    private Context context;

    public TaskAdapter(ArrayList<Task> taskList, Context context) {
        this.taskList = taskList;
        this.context = context;
    }

    @Override
    public int getCount() {
        return taskList.size();
    }

    @Override
    public Object getItem(int position) {
        return taskList.get(position);
    }

    @Override
    public long getItemId(int itemId) {
        return itemId;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Task task = taskList.get(position);
        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.listitem_task, parent, false);
        }

        int taskHrsEnd = task.getHrsEnd();
        int taskHrsStart = task.getHrsStart();
        int taskMinsStart = task.getMinsStart();
        int taskMinsEnd = task.getMinsEnd();
        Button taskField = (Button) convertView.findViewById(R.id.task_field);
        taskField.setText(task.getName() + " (" + task.getDurationMins() + "m)");
        Button timeField = (Button) convertView.findViewById(R.id.time_field);

        if (task.isChecked()) {
            taskField.setBackgroundResource(R.color.transparent_white_col);
            timeField.setBackgroundResource(R.color.transparent_white_col);
        } else {
            taskField.setBackgroundResource(R.color.white_col);
            timeField.setBackgroundResource(R.color.white_col);
        }

        // FORMATTING TIME-FIELD:
        if (taskHrsStart < 10 && taskMinsStart > 9) {                
            timeField.setText("0" + taskHrsStart + ":" + taskMinsStart);
        }
        if (taskHrsStart > 9 && taskMinsStart < 10) {
            timeField.setText(taskHrsStart + ":0" + taskMinsStart);
        }
        if (taskHrsStart > 9 && taskMinsStart > 9) {
            timeField.setText(taskHrsStart + ":" + taskMinsStart);
        }
        if (taskHrsStart < 10 && taskMinsStart < 10) {
            timeField.setText("0" + taskHrsStart + ":0" + taskMinsStart);
        }
        if (taskHrsEnd < 10 && taskMinsEnd > 9) {
            timeField.append(" - " + "0" + taskHrsEnd + ":" + taskMinsEnd);
        }
        if (taskHrsEnd > 9 && taskMinsEnd < 10) {
            timeField.append(" - " + taskHrsEnd + ":0" + taskMinsEnd);
        }
        if (taskHrsEnd > 9 && taskMinsEnd > 9) {
            timeField.append(" - " + taskHrsEnd + ":" + taskMinsEnd);
        }
        if (taskHrsEnd < 10 && taskMinsEnd < 10) {
            timeField.append(" - " + "0" + taskHrsEnd + ":0" + task.getMinsEnd());
        }


        return convertView;
    }
}

我从 MainActivity.java 中调用它：

public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor>, AdapterView.OnItemClickListener {
    private ArrayList<Task> taskList;
    private ListView listView;   
    private TaskAdapter taskAdapter; 

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        init();
    }

    private void init() {
        findViewById(R.id.btn_back).setVisibility(View.GONE);
        findViewById(R.id.btn_delete_selected).setVisibility(View.GONE);

        taskList = new ArrayList<>();

        viewTimeRemain = (TextView) findViewById(R.id.time_remain_view);
        listView = (ListView) findViewById(R.id.task_list);
        listView.setOnItemClickListener(this);
        registerForContextMenu(listView);
        taskAdapter = new TaskAdapter(taskList, this);
    }

    public void addTask(View view) {
        EditText taskName = (EditText) findViewById(R.id.taskName);
        EditText taskDuration = (EditText) findViewById(R.id.taskDuration);
        Task task = new Task();                                                   
        task.setName(taskName.getText().toString());                              
      task.setDurationMins(Integer.parseInt(taskDuration.getText().toString()));
        setTaskTimeInterval(task);
        taskList.add(task);       
        fillList(taskAdapter);  

    private void fillList(TaskAdapter taskAdapter) {  
        listView.setAdapter(taskAdapter);             
    }
}

崩溃报告：

java.lang.IndexOutOfBoundsException                                                    
    at android.graphics.Paint.getTextRunAdvances(Paint.java:1879)                      
    at android.text.TextLine.handleText(TextLine.java:747)                             
    at android.text.TextLine.handleRun(TextLine.java:898)                              
    at android.text.TextLine.measureRun(TextLine.java:414)                             
    at android.text.TextLine.measure(TextLine.java:293)                                
    at android.text.TextLine.metrics(TextLine.java:267)                                
    at android.text.Layout.getLineExtent(Layout.java:976)                              
    at android.text.Layout.getLineMax(Layout.java:932)                                 
    at android.text.Layout.getLineLeft(Layout.java:889)                                
    at android.widget.TextView.bringTextIntoView(TextView.java:6652)                   
    at android.widget.TextView.onPreDraw(TextView.java:4696)                           
    at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:847)      
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1867)             
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)                    
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)         
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)           
    at android.view.Choreographer.doCallbacks(Choreographer.java:574)                  
    at android.view.Choreographer.doFrame(Choreographer.java:544)                      
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
    at android.os.Handler.handleCallback(Handler.java:733)                             
    at android.os.Handler.dispatchMessage(Handler.java:95)                             
    at android.os.Looper.loop(Looper.java:136)                                         
    at android.app.ActivityThread.main(ActivityThread.java:5001)                       
    at java.lang.reflect.Method.invokeNative(Native Method)                            
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)                    
    at dalvik.system.NativeStart.main(Native Method)

请帮我理解这个问题！谢谢！

Answer 1

我发现当我尝试将.append（）文本添加到TextView（Button）时会发生这种错误。所以我使用StringBuffer来构造我需要的文本，然后将这个文本设置为我的TextView（不附加），它现在可以正常工作。

ListView适配器无法与AppCompatActivity

1 个答案: