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  • java/
  • java.lang.NullPointerException:uriString

java.lang.NullPointerException:uriString

java android

java.lang.NullPointerException:uriString,java,android,nullpointerexception,uri,android-video-player,Java,Android,Nullpointerexception,Uri,Android Video Player,我是一个新手，正在尝试创建一个视频播放器。我遇到了一个空指针异常，我已经阅读了SO上的所有问题，搜索了与之相关的google并阅读了它拇指路径对我来说似乎不为空，尽管这可能是此异常的唯一原因。有人能帮我吗？谢谢 SDVideos.java package com.example.dell_1.myapp3; import android.app.Activity; import android.content.Context; import android.database.Cursor; i

我是一个新手，正在尝试创建一个视频播放器。我遇到了一个空指针异常，我已经阅读了SO上的所有问题，搜索了与之相关的google并阅读了它<代码>拇指路径对我来说似乎不为空，尽管这可能是此异常的唯一原因。有人能帮我吗？谢谢

SDVideos.java

package com.example.dell_1.myapp3;

import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

public class SDVideos extends Activity
{
    private Cursor videoCursor;
    private int videoColumnIndex;
    ListView videolist;
    int count;
    String thumbPath;

    String[] thumbColumns = { MediaStore.Video.Thumbnails.DATA,MediaStore.Video.Thumbnails.VIDEO_ID };
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sdvideos);
        initialization();
    }

    private void initialization()
    {
        System.gc();
        String[] videoProjection = { MediaStore.Video.Media._ID,MediaStore.Video.Media.DATA,
                MediaStore.Video.Media.DISPLAY_NAME,MediaStore.Video.Media.SIZE };
        videoCursor =getContentResolver().query(MediaStore.Video.Media.EXTERNAL_CONTENT_URI,videoProjection, null, null, null);
        count = videoCursor.getCount();
        videolist = (ListView) findViewById(R.id.PhoneVideoList);

        videolist.setAdapter(new VideoListAdapter(this.getApplicationContext()));
        videolist.setOnItemClickListener(videogridlistener);
    }

    private AdapterView.OnItemClickListener videogridlistener = new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView parent, View v, int position, long id)
        {
            videoColumnIndex = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA);
            videoCursor.moveToPosition(position);
            String filename = videoCursor.getString(videoColumnIndex);
            Log.i("FileName: ", filename);
//Intent intent = new Intent(VideoActivity.this, ViewVideo.class);
//intent.putExtra("videofilename", filename);
//startActivity(intent);
        }};

    public class VideoListAdapter extends BaseAdapter
    {
        private Context vContext;

        public VideoListAdapter(Context c)
        {
            vContext = c;
        }

        public int getCount()
        {
            return videoCursor.getCount();
        }

        public Object getItem(int position)
        {
            return position;
        }

        public long getItemId(int position)
        {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent)
        {
            View listItemRow;
            listItemRow = LayoutInflater.from(vContext).inflate(R.layout.listitem, parent, false);

            TextView txtTitle = (TextView)listItemRow.findViewById(R.id.txtTitle);
            TextView txtSize = (TextView)listItemRow.findViewById(R.id.txtSize);
            ImageView thumbImage = (ImageView)listItemRow.findViewById(R.id.imgIcon);

            videoColumnIndex = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME);
            videoCursor.moveToPosition(position);
            txtTitle.setText(videoCursor.getString(videoColumnIndex));

            videoColumnIndex = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE);
            videoCursor.moveToPosition(position);
            txtSize.setText(" Size(KB):" + videoCursor.getString(videoColumnIndex));

            int videoId = videoCursor.getInt(videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));
            Cursor videoThumbnailCursor =getContentResolver().query(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI,
                    thumbColumns, MediaStore.Video.Thumbnails.VIDEO_ID+ "=" + videoId, null, null);

            if (videoThumbnailCursor.moveToFirst())
            {
                thumbPath = videoThumbnailCursor.getString(videoThumbnailCursor.getColumnIndex(MediaStore.Video.Thumbnails.DATA));
                Log.i("ThumbPath: ",thumbPath);
            }
            thumbImage.setImageURI(Uri.parse(thumbPath));
            return listItemRow;
        }
    }
}
XML文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">
    <ListView
        android:id="@+id/PhoneVideoList"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:divider="#242424"
        android:dividerHeight="1dp"/>
    </LinearLayout>

08-05 17:29:17.109 17708-17708/com.example.dell_1.myapp3 E/AndroidRuntime: FATAL EXCEPTION: main
        Process: com.example.dell_1.myapp3, PID: 17708
        java.lang.NullPointerException: uriString
        at android.net.Uri$StringUri.<init>(Uri.java:475)
    at android.net.Uri$StringUri.<init>(Uri.java)
    at android.net.Uri.parse(Uri.java:437)
    at com.example.dell_1.myapp3.SDVideos$VideoListAdapter.getView(SDVideos.java:112)
    at android.widget.AbsListView.obtainView(AbsListView.java:2367)
    at android.widget.ListView.makeAndAddView(ListView.java:1972)
    at android.widget.ListView.fillDown(ListView.java:704)
    at android.widget.ListView.fillFromTop(ListView.java:765)
    at android.widget.ListView.layoutChildren(ListView.java:1744)
    at android.widget.AbsListView.onLayout(AbsListView.java:2161)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at com.android.internal.policy.DecorView.onLayout(DecorView.java:724)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2374)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2101)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1278)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6357)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
    at android.view.Choreographer.doCallbacks(Choreographer.java:683)
    at android.view.Choreographer.doFrame(Choreographer.java:619)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6077)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
LOGCAT:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">
    <ListView
        android:id="@+id/PhoneVideoList"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:divider="#242424"
        android:dividerHeight="1dp"/>
    </LinearLayout>

08-05 17:29:17.109 17708-17708/com.example.dell_1.myapp3 E/AndroidRuntime: FATAL EXCEPTION: main
        Process: com.example.dell_1.myapp3, PID: 17708
        java.lang.NullPointerException: uriString
        at android.net.Uri$StringUri.<init>(Uri.java:475)
    at android.net.Uri$StringUri.<init>(Uri.java)
    at android.net.Uri.parse(Uri.java:437)
    at com.example.dell_1.myapp3.SDVideos$VideoListAdapter.getView(SDVideos.java:112)
    at android.widget.AbsListView.obtainView(AbsListView.java:2367)
    at android.widget.ListView.makeAndAddView(ListView.java:1972)
    at android.widget.ListView.fillDown(ListView.java:704)
    at android.widget.ListView.fillFromTop(ListView.java:765)
    at android.widget.ListView.layoutChildren(ListView.java:1744)
    at android.widget.AbsListView.onLayout(AbsListView.java:2161)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at com.android.internal.policy.DecorView.onLayout(DecorView.java:724)
    at android.view.View.layout(View.java:17523)
    at android.view.ViewGroup.layout(ViewGroup.java:5618)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2374)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2101)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1278)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6357)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
    at android.view.Choreographer.doCallbacks(Choreographer.java:683)
    at android.view.Choreographer.doFrame(Choreographer.java:619)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6077)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

08-05 17:29:17.109 17708-17708/com.example.dell_1.myapp3 E/AndroidRuntime:致命异常：main
进程：com.example.dell_1.myapp3，PID:17708
java.lang.NullPointerException:uriString
在android.net.Uri$StringUri。（Uri.java:475）
在android.net.Uri$StringUri.（Uri.java）
位于android.net.Uri.parse（Uri.java:437）
位于com.example.dell_1.myapp3.SDVideos$VideoListAdapter.getView（SDVideos.java:112）
在android.widget.AbsListView.obtainView（AbsListView.java:2367）
位于android.widget.ListView.makeAndAddView（ListView.java:1972）
在android.widget.ListView.fillDown（ListView.java:704）中
位于android.widget.ListView.fillFromTop（ListView.java:765）
位于android.widget.ListView.layoutChildren（ListView.java:1744）
在android.widget.AbsListView.onLayout（AbsListView.java:2161）
位于android.view.view.layout（view.java:17523）
位于android.view.ViewGroup.layout（ViewGroup.java:5618）
位于android.widget.LinearLayout.setChildFrame（LinearLayout.java:1741）
位于android.widget.LinearLayout.layoutVertical（LinearLayout.java:1585）
位于android.widget.LinearLayout.onLayout（LinearLayout.java:1494）
位于android.view.view.layout（view.java:17523）
位于android.view.ViewGroup.layout（ViewGroup.java:5618）
位于android.widget.FrameLayout.layoutChildren（FrameLayout.java:323）
位于android.widget.FrameLayout.onLayout（FrameLayout.java:261）
位于android.view.view.layout（view.java:17523）
位于android.view.ViewGroup.layout（ViewGroup.java:5618）
位于android.widget.LinearLayout.setChildFrame（LinearLayout.java:1741）
位于android.widget.LinearLayout.layoutVertical（LinearLayout.java:1585）
位于android.widget.LinearLayout.onLayout（LinearLayout.java:1494）
位于android.view.view.layout（view.java:17523）
位于android.view.ViewGroup.layout（ViewGroup.java:5618）
位于android.widget.FrameLayout.layoutChildren（FrameLayout.java:323）
位于android.widget.FrameLayout.onLayout（FrameLayout.java:261）
位于com.android.internal.policy.DecorView.onLayout（DecorView.java:724）
位于android.view.view.layout（view.java:17523）
位于android.view.ViewGroup.layout（ViewGroup.java:5618）
在android.view.ViewRootImpl.performLayout（ViewRootImpl.java:2374）
在android.view.ViewRootImpl.performTraversals上（ViewRootImpl.java:2101）
位于android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1278）
在android.view.ViewRootImpl$TraversalRunnable.run（ViewRootImpl.java:6357）
在android.view.Choreographer$CallbackRecord.run（Choreographer.java:871）
位于android.view.Choreographer.doCallbacks（Choreographer.java:683）
位于android.view.Choreographer.doFrame（Choreographer.java:619）
在android.view.Choreographer$FrameDisplayEventReceiver.run（Choreographer.java:857）中
位于android.os.Handler.handleCallback（Handler.java:751）
位于android.os.Handler.dispatchMessage（Handler.java:95）
位于android.os.Looper.loop（Looper.java:154）
位于android.app.ActivityThread.main（ActivityThread.java:6077）
位于java.lang.reflect.Method.invoke（本机方法）
在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:865）上
位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:755）
我看不出为什么thumbPath需要成为SDVideos字段，它只在VideoListAdapter.getView中使用

将thumbPath作为变量移动的更新代码如下：

 int videoId = videoCursor.getInt(videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));
        Cursor videoThumbnailCursor =getContentResolver().query(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI,
                thumbColumns, MediaStore.Video.Thumbnails.VIDEO_ID+ "=" + videoId, null, null);

        if (videoThumbnailCursor.moveToFirst())
        {
            String thumbPath = videoThumbnailCursor.getString(videoThumbnailCursor.getColumnIndex(MediaStore.Video.Thumbnails.DATA));
            Log.i("ThumbPath: ",thumbPath);
            thumbImage.setImageURI(Uri.parse(thumbPath));
        }

        return listItemRow;
由于只有在光标有任何数据时才会填充thumbPath，因此可以将setImageURI移动到if中

这段代码将解决NullPointerException，但您可能不会在thumbImage中看到任何图像

现在，您需要找到videoThumbnailCursor不返回任何数据的原因。找到原因后，请更新您的问题。

我不认为thumbPath需要成为SDVideos字段的任何原因，它仅在VideoListAdapter.getView中使用

将thumbPath作为变量移动的更新代码如下：

 int videoId = videoCursor.getInt(videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));
        Cursor videoThumbnailCursor =getContentResolver().query(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI,
                thumbColumns, MediaStore.Video.Thumbnails.VIDEO_ID+ "=" + videoId, null, null);

        if (videoThumbnailCursor.moveToFirst())
        {
            String thumbPath = videoThumbnailCursor.getString(videoThumbnailCursor.getColumnIndex(MediaStore.Video.Thumbnails.DATA));
            Log.i("ThumbPath: ",thumbPath);
            thumbImage.setImageURI(Uri.parse(thumbPath));
        }

        return listItemRow;
由于只有在光标有任何数据时才会填充thumbPath，因此可以将setImageURI移动到if中

这段代码将解决NullPointerException，但您可能不会在thumbImage中看到任何图像

现在，您需要找到videoThumbnailCursor不返回任何数据的原因。找到原因后，请更新您的问题。

崩溃日志在哪里？请将其包含在您的帖子中抱歉，我现在将其包含在@umarzaii中导致错误的是哪一行？崩溃日志在哪里？请将其包含在您的帖子中抱歉，我现在包含了@umarzaii导致错误的那一行？非常感谢，实际上我看到了一些文件的缩略图，但不是所有文件的缩略图@jonathanrzI修复了它，谢谢，现在获取所有文件的缩略图：）非常感谢，事实上，我看到了一些文件的缩略图，但不是所有文件的缩略图@jonathanrzI修复了它，谢谢，现在获得所有文件的缩略图：）