So I have created this new list view with a custom object and a custom adapter. But my activity just crashes whenever I start the app. Im a beginner so please explain me my mistake.
This is my MainACtivity
public class MainActivity extends ListActivity {
private ArrayList<Android> androids = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
androids.add(new Android(R.drawable.android_a, R.string.android_a, R.string.data_a));
androids.add(new Android(R.drawable.android_a, R.string.android_b, R.string.data_b));
androids.add(new Android(R.drawable.cupcake, R.string.name_cupcake, R.string.data_c));
androids.add(new Android(R.drawable.donut, R.string.name_donut, R.string.data_d));
androids.add(new Android(R.drawable.ecalir, R.string.name_eclairs, R.string.data_e));
androids.add(new Android(R.drawable.froyo, R.string.name_froyo, R.string.data_f));
androids.add(new Android(R.drawable.gb, R.string.name_ginderbread, R.string.data_g));
androids.add(new Android(R.drawable.honeycomb, R.string.name_honeycomb, R.string.data_h));
androids.add(new Android(R.drawable.ics, R.string.name_ics, R.string.data_i));
androids.add(new Android(R.drawable.jb, R.string.name_jb, R.string.data_j));
androids.add(new Android(R.drawable.kk, R.string.name_kitkat, R.string.data_k));
androids.add(new Android(R.drawable.lolipop, R.string.name_lolipop, R.string.data_l));
androids.add(new Android(R.drawable.mashmallow, R.string.name_mashmallow, R.string.data_m));
androids.add(new Android(R.drawable.nougat, R.string.name_nougat, R.string.data_n));
AndroidAdapter adapter = new AndroidAdapter(this, android.R.layout.simple_list_item_1, androids);
ListView listView = (ListView) findViewById(R.id.list);
listView.setAdapter(adapter);
}
}
This is my custom object
public class Android {
private int mImageResourceID;
private int mAndroidVersion;
private int mAndroidDetails;
public Android(){ }
public Android(int imageResourceID, int androidVersion , int androidDetails)
{
mImageResourceID = imageResourceID;
mAndroidVersion = androidVersion;
mAndroidDetails = androidDetails;
}
int getImageResourceID()
{
return mImageResourceID;
}
int getAndroidVersion()
{
return mAndroidVersion;
}
int getAndroidDetails()
{
return mAndroidDetails;
}
}
This is my custom adapter
public class AndroidAdapter extends ArrayAdapter<Android> {
private ArrayList<Android> android;
public AndroidAdapter(Context context, int resource , ArrayList<Android>android) {
super(context, resource,android);
this.android = android;
}
@NonNull
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if(v==null)
{
LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.list_view , null);
}
Android i = android.get(position);
if(i!= null)
{
ImageView image = (ImageView) v.findViewById(R.id.image_android);
TextView androidName = (TextView) v.findViewById(R.id.android_name);
TextView androidDetails = (TextView) v.findViewById(R.id.android_details);
image.setImageResource(i.getImageResourceID());
androidName.setText(i.getAndroidVersion());
androidDetails.setText(i.getAndroidDetails());
}
return v;
}
}
This is the error message I get
11-03 22:25:40.531 31629-31629/com.example.android.android E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.android, PID: 31629
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.android/com.example.android.android.MainActivity}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3319)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3415)
at android.app.ActivityThread.access$1100(ActivityThread.java:229)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:7325)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
at android.app.ListActivity.onContentChanged(ListActivity.java:243)
at com.android.internal.policy.PhoneWindow.setContentView(PhoneWindow.java:492)
at android.app.Activity.setContentView(Activity.java:2400)
at com.example.android.android.MainActivity.onCreate(MainActivity.java:24)
at android.app.Activity.performCreate(Activity.java:6904)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3266)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3415)
at android.app.ActivityThread.access$1100(ActivityThread.java:229)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:7325)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
11-03 22:25:43.121 31629-31629/com.example.android.android I/
Process: Sending signal. PID: 31629 SIG: 9
Please help me with this.
