我正在开发一个必须在包含图片的主要活动中有GridView的应用程序。
单击图像时，必须以更大的尺寸打开另一个Activity。在此Activity中，必须实施ViewPager，以便我可以左右滑动以在图像之间切换。
我已经完成了很大一部分工作，我不知道问题出在哪里但是当我点击图片时，应用程序崩溃了。有人可以帮帮我吗？
这是我的主要活动代码：
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBarActivity;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.GridView;
public class MainActivityPager extends ActionBarActivity
{
static int[] FLAG;
ViewPager viewPager;
PagerAdapter adapter;
GridView gridview;
int count;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity_pager);
FLAG = new int[] { R.drawable.flag_of_argentina, R.drawable.flag_of_brazil,
R.drawable.flag_of_england, R.drawable.flag_of_france,
R.drawable.flag_of_germany, R.drawable.flag_of_italy, R.drawable.flag_of_spain,
R.drawable.flag_of_uruguay };
AdapterGrid adapter = new AdapterGrid(MainActivityPager.this, FLAG);
gridview = (GridView) findViewById(R.id.gridView1);
gridview.setAdapter(adapter);
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id)
{
Intent intent = new Intent(view.getContext(), ActivityImage.class);
intent.putExtra("position", position);
count = gridview.getCount();
intent.putExtra("count", count);
startActivity(intent);
}
});
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
这是我的AdapterGrid类代码：
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
public class AdapterGrid extends BaseAdapter
{
private int[] mFlag;
private Context mContext;
public AdapterGrid(Context context, int[] flag) {
//super(context, flag);
mContext = context;
mFlag = flag;
}
@Override
public int getCount() {
return mFlag.length;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
View grid;
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
{
grid = new View(mContext);
grid = inflater.inflate(R.layout.grid_single, null);
ImageView imageView = (ImageView)grid.findViewById(R.id.grid_image);
imageView.setImageResource(mFlag[position]);
} else {
grid = (View) convertView;
}
return grid;
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
}
这是我的ActivityImage代码：
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.Menu;
public class ActivityImage extends FragmentActivity
{
private static int COUNT;
MyAdapter mAdapter;
ViewPager mPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_activity_image);
Intent intent = getIntent();
COUNT = intent.getExtras().getInt("count");
mAdapter = new MyAdapter(getSupportFragmentManager());
mPager = (ViewPager) findViewById(R.id.pager);
mPager.setAdapter(mAdapter);
}
public static class MyAdapter extends FragmentPagerAdapter {
public MyAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
}
@Override
public int getCount() {
return COUNT;
}
@Override
public Fragment getItem(int position) {
return FragmentImage.init(position);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_image, menu);
return true;
}
}
这是我的FragmentImage类代码：
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
public class FragmentImage extends Fragment {
int fragVal;
static FragmentImage init(int pos) {
FragmentImage frag = new FragmentImage();
Bundle args = new Bundle();
args.putInt("val", pos);
frag.setArguments(args);
return frag;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
fragVal = getArguments() != null ? getArguments().getInt("val") : 1;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View layoutView = inflater.inflate(R.layout.fragment_image, container,
false);
ImageView imageView = (ImageView) layoutView.findViewById(R.id.imageView1);
imageView.setImageResource(MainActivityPager.FLAG[fragVal]);
return layoutView;
}
}
这些是我的logcat错误：
07-22 09:40:29.915: E/MoreInfoHPW_ViewGroup(25934): Parent view is not a TextView
07-22 09:40:29.920: E/AndroidRuntime(25934): FATAL EXCEPTION: main
07-22 09:40:29.920: E/AndroidRuntime(25934): Process: com.example.gridviewpager, PID: 25934
07-22 09:40:29.920: E/AndroidRuntime(25934): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.gridviewpager/com.example.gridviewpager.ActivityImage}: java.lang.NullPointerException
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2282)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2340)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.ActivityThread.access$800(ActivityThread.java:157)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1247)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.os.Handler.dispatchMessage(Handler.java:102)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.os.Looper.loop(Looper.java:157)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.ActivityThread.main(ActivityThread.java:5293)
07-22 09:40:29.920: E/AndroidRuntime(25934): at java.lang.reflect.Method.invokeNative(Native Method)
07-22 09:40:29.920: E/AndroidRuntime(25934): at java.lang.reflect.Method.invoke(Method.java:515)
07-22 09:40:29.920: E/AndroidRuntime(25934): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
07-22 09:40:29.920: E/AndroidRuntime(25934): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
07-22 09:40:29.920: E/AndroidRuntime(25934): at dalvik.system.NativeStart.main(Native Method)
07-22 09:40:29.920: E/AndroidRuntime(25934): Caused by: java.lang.NullPointerException
07-22 09:40:29.920: E/AndroidRuntime(25934): at com.example.gridviewpager.ActivityImage.onCreate(ActivityImage.java:27)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.Activity.performCreate(Activity.java:5389)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
07-22 09:40:29.920: E/AndroidRuntime(25934): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2246)
07-22 09:40:29.920: E/AndroidRuntime(25934): ... 11 more
答案 0 :(得分：0)
Intent intent = new Intent(getApplicationContext, ActivityImage.class);
intent.putExtra("position", position);
count = gridview.getCount();
intent.putExtra("count", count);
startActivity(intent);
public Object getItem(int position) {
return FLAG[posotion];
}
@Override
public long getItemId(int position) {
return (long)position;
}
答案 1 :(得分：0)
似乎mPager是null。检查pager布局中是否确实包含ID activity_activity_image.xml。