我的 Android 项目遇到问题。它是一个音乐曲目播放器，显示 ListFragment 中的每个曲目。每个项目都有一个位图，其中示波器绘制在位图画布上。
Listfragment 中的项目会定期刷新。这是通过以下方式完成的
通知数据集更改（）；
我还想在单击该项目时将一个轨道静音，但 onItemClick 事件不会每次都被触发。只是有时。谁能向我解释一下吗？我在这里做错了什么？
它在没有notifyDataSetChanged()的情况下完美工作，但随后项目不会刷新。
Thanks!
这是完整的代码：
主要活动：
package de.sma.stackoverflow;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
我的列表片段
package de.sma.stackoverflow;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import android.app.ListFragment;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
public class MyListFragment extends ListFragment implements OnItemClickListener
{
ListViewAdapter adapter;
private List<ListViewItem> rowItems;
private Handler sampleUpdateHandler = new Handler();
Paint paintText = new Paint(Paint.ANTI_ALIAS_FLAG);
boolean bMuted = false;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
return inflater.inflate(R.layout.fragment_list_layout, null, false);
}
@Override
public void onActivityCreated(Bundle savedInstanceState)
{
super.onActivityCreated(savedInstanceState);
paintText.setColor(Color.WHITE);
paintText.setStyle(Paint.Style.FILL);
rowItems = new ArrayList<ListViewItem>();
rowItems.add(new ListViewItem("Android"));
rowItems.add(new ListViewItem("iOS"));
rowItems.add(new ListViewItem("Symbian"));
rowItems.add(new ListViewItem("Blackberry"));
rowItems.add(new ListViewItem("Windows Phone"));
rowItems.add(new ListViewItem("Galaxy Nexus"));
rowItems.add(new ListViewItem("Offline"));
adapter = new ListViewAdapter(getActivity(), rowItems);
setListAdapter(adapter);
getListView().setOnItemClickListener(this);
StartThread();
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
Log.d("WhyDoesntThisWork", "onListItemClick");
bMuted = !bMuted;
}
private void StartThread()
{
new Thread(new Runnable()
{
Random rand = new Random();
public int randInt(int min, int max)
{
int randomNum = rand.nextInt((max - min) + 1) + min;
return randomNum;
}
@Override
public void run()
{
while (true)
{
try
{
Thread.sleep(10);
sampleUpdateHandler.post(new Runnable()
{
@Override
public void run()
{
Canvas myCanvas = rowItems.get(0).getCanvas();
if (bMuted)
myCanvas.drawColor(0xFFFF0000);
else
myCanvas.drawColor(0xFF000020);
for (int i = 0; i < myCanvas.getWidth(); i++)
myCanvas.drawLine(i, randInt(0, 50), i + 1, randInt(0, 50), paintText);
adapter.notifyDataSetChanged();
}
});
} catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
}).start();
}
}
列表视图项：
package de.sma.stackoverflow;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.widget.ImageView;
public class ListViewItem
{
private String title;
private Bitmap mBitmap;
private Canvas mCanvas;
private ImageView mImageView;
public ListViewItem(String title)
{
this.title = title;
mBitmap = Bitmap.createBitmap(100, 50, Bitmap.Config.RGB_565);
mCanvas = new Canvas(mBitmap);
mCanvas.drawColor(0xFF2020FF);
}
public Canvas getCanvas()
{
return mCanvas;
}
public String getTitle()
{
return title;
}
public Bitmap getBitmap()
{
return mBitmap;
}
public void setImageView(ImageView imageView)
{
this.mImageView = imageView;
}
}
列表视图适配器：
package de.sma.stackoverflow;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.List;
public class ListViewAdapter extends BaseAdapter
{
Context context;
List<ListViewItem> rowItem;
ListViewAdapter(Context context, List<ListViewItem> rowItem)
{
this.context = context;
this.rowItem = rowItem;
}
@Override
public int getCount()
{
return rowItem.size();
}
@Override
public Object getItem(int position)
{
return rowItem.get(position);
}
@Override
public long getItemId(int position)
{
return rowItem.indexOf(getItem(position));
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
if (convertView == null)
{
LayoutInflater mInflater = (LayoutInflater) context
.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
convertView = mInflater.inflate(R.layout.list_item, null);
}
TextView txtTitle = (TextView) convertView.findViewById(R.id.title);
ListViewItem row_pos = rowItem.get(position);
// setting the image resource and title
txtTitle.setText(row_pos.getTitle());
ImageView imageView = (ImageView) convertView.findViewById(R.id.icon);
imageView.setImageBitmap(row_pos.getBitmap());
row_pos.setImageView(imageView);
return convertView;
}
}
主要布局：
<?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="vertical" >
<fragment
android:id="@+id/fragment1"
android:name="de.sma.stackoverflow.MyListFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
列表布局：
<?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="vertical" >
<ListView
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
<TextView
android:id="@android:id/empty"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</TextView>
</LinearLayout>
项目清单：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="50dp"
android:padding="5dp" >
<ImageView
android:id="@+id/icon"
android:layout_width="100dp"
android:layout_height="50dp"
android:layout_alignParentLeft="true"
android:layout_marginLeft="12dp"
android:layout_marginRight="12dp"
android:contentDescription="imgdesc"
android:layout_alignParentTop="true"/>
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_marginTop="10dp"
android:layout_toRightOf="@id/icon"
android:gravity="center_vertical"
android:textColor="#000000"
android:textSize="20sp"
android:text="test"/>
</RelativeLayout>
