Android 正在更正logcat错误“尝试写入空数组”
我正在编写一个非常基本的家庭启动器,我在AppsGridActivity中创建了一个类AppsInfoModel、一个CustomAdapter和一个GridView 下面是我在活动中填充适配器的代码Android 正在更正logcat错误“尝试写入空数组”,android,Android,我正在编写一个非常基本的家庭启动器,我在AppsGridActivity中创建了一个类AppsInfoModel、一个CustomAdapter和一个GridView 下面是我在活动中填充适配器的代码 appsGrid = (GridView) findViewById(R.id.appsGrid); appsInfo = new AppsInfoModel(this); appsGrid.setAdapter(new CustomAdapter(this,appsInf
appsGrid = (GridView) findViewById(R.id.appsGrid);
appsInfo = new AppsInfoModel(this);
appsGrid.setAdapter(new CustomAdapter(this,appsInfo));
这是适配器
public class CustomAdapter extends BaseAdapter {
Context context;
AppsInfoModel appInfo;
CustomAdapter(Context context,AppsInfoModel appInfo) {
this.context = context;
this.appInfo = appInfo;
}
@Override
public int getCount() {
return appInfo.getSize();
}
@Override
public Object getItem(int position) {
return appInfo.getItem(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
convertView = inflater.inflate(R.layout.single_grid, parent, false);
ImageView icon = (ImageView) convertView.findViewById(R.id.app_icon);
icon.setImageDrawable(appInfo.getIcon(position));
TextView label = (TextView) convertView.findViewById(R.id.app_label);
label.setText(appInfo.getLabel(position));
return convertView;
}
else
return convertView;
}
}
模型班
public class AppsInfoModel {
String label[];
String name[];
Drawable icon[];
PackageManager pm;
List<ResolveInfo> appsInfo;
AppsInfoModel(Context context){
pm=context.getPackageManager();
appsInfo = pm.queryIntentActivities(new Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_LAUNCHER), 0);
for(int i=0;i<appsInfo.size();i++){
label[i]= (appsInfo.get(i).loadLabel(pm)).toString();//***This is where problem lies according to LogCat***
name[i]= (appsInfo.get(i)).activityInfo.packageName;
icon[i]=(appsInfo.get(i)).activityInfo.loadIcon(pm);
}
}
Drawable getIcon(int i){
return icon[i];
}
String getLabel(int i){
return label[i];
}
String getPackageName(int i){
return name[i];
}
int getSize(){
return appsInfo.size();
}
public ResolveInfo getItem(int i) {
return appsInfo.get(i);
}
}
这是Logcat错误
java.lang.RuntimeException: Unable to start activity ComponentInfo{example.home/example.home.AppsGridActivity}: java.lang.NullPointerException: Attempt to write to null array
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to write to null array
at example.home.AppsInfoModel.<init>(AppsInfoModel.java:25)
at example.home.AppsGridActivity.onCreate(AppsGridActivity.java:21)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
为什么会这样?
逻辑或语法有什么问题。根据您发布的代码,您没有初始化这些数组:
String label[];
String name[];
Drawable icon[];
你应该这样做:
AppsInfoModel(Context context){
pm=context.getPackageManager();
appsInfo = pm.queryIntentActivities(new Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_LAUNCHER), 0);
label = new String[appsInfo.size()];
name = new String[appsInfo.size()];
icon = new Drawable[appsInfo.size()];
for(int i=0;i<appsInfo.size();i++){
label[i]= (appsInfo.get(i).loadLabel(pm)).toString();
name[i]= (appsInfo.get(i)).activityInfo.packageName;
icon[i]=(appsInfo.get(i)).activityInfo.loadIcon(pm);
}
}
根据您发布的代码,您没有初始化这些数组:
String label[];
String name[];
Drawable icon[];
你应该这样做:
AppsInfoModel(Context context){
pm=context.getPackageManager();
appsInfo = pm.queryIntentActivities(new Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_LAUNCHER), 0);
label = new String[appsInfo.size()];
name = new String[appsInfo.size()];
icon = new Drawable[appsInfo.size()];
for(int i=0;i<appsInfo.size();i++){
label[i]= (appsInfo.get(i).loadLabel(pm)).toString();
name[i]= (appsInfo.get(i)).activityInfo.packageName;
icon[i]=(appsInfo.get(i)).activityInfo.loadIcon(pm);
}
}
AppsInfoModel.java中的第25行是什么。这是因为数组为空。AppsInfoModel.java中的第25行是什么。这是因为您的数组为空。Thanx,它完成了位。很高兴我能够帮助您:Thanx,它完成了位。很高兴我能够帮助您: