我刚接触到android。这个应用程序是教程的一部分。现在我想知道为什么如果我点击gridview的项目会崩溃。我已经阅读了日志，但不知道错误的演员阵容在哪里。
public class MainActivity extends Activity implements OnItemClickListener {
GridView myGrid;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myGrid=(GridView) findViewById(R.id.gridView);
myGrid.setAdapter(new CustomAdapter(this));
myGrid.setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
Intent intent=new Intent(this, Dialog.class);
ViewHolder holder=(ViewHolder) view.getTag();
AppName temp=(AppName) holder.AppImage.getTag();
intent.putExtra("appImage", temp.image);
intent.putExtra("appName", temp.appname);
startActivity(intent);
}
}
class AppName{
int image;
String appname;
AppName(int image, String appname){
this.image=image;
this.appname=appname;
}
}
class ViewHolder{
ImageView AppImage;
ViewHolder(View v){
AppImage=(ImageView) v.findViewById(R.id.imageView1);
}
}
class CustomAdapter extends BaseAdapter{
ArrayList<AppName> list;
Context context;
public CustomAdapter(Context c) {
this.context=c;
list= new ArrayList<AppName>();
Resources res=c.getResources();
String[] Appnames=res.getStringArray(R.array.Appnames);
int[] images=R.drawable.aim,R.drawable.amazon,R.drawable.amazon2,R.drawable.android,R.drawable.aol,R.drawable.apple,R.drawable.appstore,R.drawable.bebo,R.drawable.behance,R.drawable.bing,R.drawable.bleetbox,R.drawable.blinklist,R.drawable.blogger,R.drawable.brightkite1,R.drawable.brightkite2,R.drawable.cargocollective,R.drawable.coroflot,R.drawable.delicious,R.drawable.designfloat,R.drawable.designmoo};
for(int i=0;i<20;i++){
list.add(new AppName(images[i], Appnames[i]));
}
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int i) {
return list.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(int i, View convertView, ViewGroup parent) {
ViewHolder holder=null;
View row=convertView;
if(row==null){
LayoutInflater inflater=(LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row=inflater.inflate(R.layout.single_item, parent, false);
holder=new ViewHolder(row);
row.setTag(holder);
}
else{
holder=(ViewHolder) row.getTag();
}
AppName temp=list.get(i);
holder.AppImage.setImageResource(temp.image);
holder.AppImage.setTag(temp);
return row;
}
}
public class Dialog extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dialog);
Intent intent=getIntent();
if(intent!=null){
int imageId=intent.getIntExtra("appImage", R.drawable.aim);
String appName=intent.getStringExtra("appName");
ImageView DialogImage=(ImageView) findViewById(R.id.imageViewDialog);
DialogImage.setImageResource(imageId);
TextView DialogText=(TextView) findViewById(R.id.imageViewDialog);
DialogText.setText("This Icon belongs to "+appName);
}
}
public void Close(View v) {
finish();
}
}
04-24 06:37:26.149: E/AndroidRuntime(2607): FATAL EXCEPTION: main
04-24 06:37:26.149: E/AndroidRuntime(2607): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nando.gridview/com.nando.gridview.Dialog}: java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.TextView
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.os.Handler.dispatchMessage(Handler.java:99)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.os.Looper.loop(Looper.java:137)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.ActivityThread.main(ActivityThread.java:5103)
04-24 06:37:26.149: E/AndroidRuntime(2607): at java.lang.reflect.Method.invokeNative(Native Method)
04-24 06:37:26.149: E/AndroidRuntime(2607): at java.lang.reflect.Method.invoke(Method.java:525)
04-24 06:37:26.149: E/AndroidRuntime(2607): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
04-24 06:37:26.149: E/AndroidRuntime(2607): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-24 06:37:26.149: E/AndroidRuntime(2607): at dalvik.system.NativeStart.main(Native Method)
04-24 06:37:26.149: E/AndroidRuntime(2607): Caused by: java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.TextView
04-24 06:37:26.149: E/AndroidRuntime(2607): at com.nando.gridview.Dialog.onCreate(Dialog.java:21)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.Activity.performCreate(Activity.java:5133)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-24 06:37:26.149: E/AndroidRuntime(2607): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
答案 0 :(得分：4)
看看你的代码，你似乎在这里写了一个拼写错误：
TextView DialogText=(TextView) findViewById(R.id.imageViewDialog);
应该是
TextView DialogText=(TextView) findViewById(R.id.textViewDialog);
或此TextView的id名称。
除此之外，您还需要学习从LogCat中读取消息，因为它们通常非常有用。 Cleary它说：
Caused by: java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.TextView
表示原因和
at com.nando.gridview.Dialog.onCreate(Dialog.java:21)
表示代码中出现的位置。
理解如何在开始时阅读堆栈跟踪可能会很痛苦，但是当您获得该堆栈跟踪时，它将节省大量时间，因为您将能够确定应用程序崩溃的原因和位置。 / p>
答案 1 :(得分：0)
您的问题在logcat中解释：
android.widget.ImageView cannot be cast to android.widget.TextView
通过查看Logcat的下一行，您可以看到它发生的位置：
at com.nando.gridview.Dialog.onCreate(Dialog.java:21)
所以改变以下内容：
TextView DialogText=(TextView) findViewById(R.id.imageViewDialog);
进入这个：
TextView DialogText=(TextView) findViewById(R.id.idofyourtextview);
答案 2 :(得分：0)
下面的错误： -
ImageView DialogImage=(ImageView) findViewById(R.id.imageViewDialog);
DialogImage.setImageResource(imageId);
或
TextView DialogText=(TextView) findViewById(R.id.imageViewDialog);
DialogText.setText("This Icon belongs to "+appName);
您将ImageView转换为textview。