我已经设置了一个带有多个选项卡的主活动，可以通过滑动进行导航。因此，每当我滑动到相应的选项卡时，片段都会显示其XML中描述的图像视图，并且此图像视图可以在点击时启用音频播放。
图像视图设置在碎片中.xml具有相应的android：onClick属性。
因此，为简单起见，让我们考虑 1 个片段（钩接到 frag.xml）和 1 个主活动（挂接到主.xml）。
现在，每当我点击图像视图时，该应用程序都不会播放任何声音，但会立即崩溃并显示以下logcat报告：
01-19 15:36:29.211: E/AndroidRuntime(20718): FATAL EXCEPTION: main
01-19 15:36:29.211: E/AndroidRuntime(20718): java.lang.IllegalStateException: Could not execute method of the activity
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.view.View$1.onClick(View.java:3640)
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.view.View.performClick(View.java:4247)
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.view.View$PerformClick.run(View.java:17728)
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.os.Handler.handleCallback(Handler.java:730)
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.os.Handler.dispatchMessage(Handler.java:92)
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.os.Looper.loop(Looper.java:137)
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.app.ActivityThread.main(ActivityThread.java:5289)
01-19 15:36:29.211: E/AndroidRuntime(20718): at java.lang.reflect.Method.invokeNative(Native Method)
01-19 15:36:29.211: E/AndroidRuntime(20718): at java.lang.reflect.Method.invoke(Method.java:525)
01-19 15:36:29.211: E/AndroidRuntime(20718): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
01-19 15:36:29.211: E/AndroidRuntime(20718): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
01-19 15:36:29.211: E/AndroidRuntime(20718): at dalvik.system.NativeStart.main(Native Method)
01-19 15:36:29.211: E/AndroidRuntime(20718): Caused by: java.lang.reflect.InvocationTargetException
01-19 15:36:29.211: E/AndroidRuntime(20718): at java.lang.reflect.Method.invokeNative(Native Method)
01-19 15:36:29.211: E/AndroidRuntime(20718): at java.lang.reflect.Method.invoke(Method.java:525)
01-19 15:36:29.211: E/AndroidRuntime(20718): at android.view.View$1.onClick(View.java:3635)
01-19 15:36:29.211: E/AndroidRuntime(20718): ... 11 more
01-19 15:36:29.211: E/AndroidRuntime(20718): Caused by: java.lang.NullPointerException
01-19 15:36:29.211: E/AndroidRuntime(20718): at com.example.MainActivity.hellofunction(MainActivity.java:63)
01-19 15:36:29.211: E/AndroidRuntime(20718): ... 14 more
01-19 15:36:30.522: I/Process(20718): Sending signal. PID: 20718 SIG: 9
碎片.xml -
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/ScrollyClips"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<RelativeLayout
android:id="@+id/RelativeLayout1"
android:layout_width="match_parent"
android:layout_height="403dp"
android:layout_marginLeft="1dp"
android:background="@color/black"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_gravity="right"
android:src="@drawable/ico" />
<ImageView
android:id="@+id/ImageView01"
android:contentDescription="solhello"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:src="@drawable/ico"
android:onClick="hellofunction"/>
</RelativeLayout>
</ScrollView>
我的Java代码如下 -
主要活动.java ：
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class MainActivity extends FragmentActivity implements ActionBar.TabListener
{
private ViewPager viewPager;
private TabsPagerAdapter adapter;
private ActionBar actionbar;
private String[] tabs={"A"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Initialize
viewPager=(ViewPager)findViewById(R.id.pager);
actionbar=getActionBar();
adapter=new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(adapter);
actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//Add tabs
for(String tab_name:tabs)
{
actionbar.addTab(actionbar.newTab().setText(tab_name)
.setTabListener(this));
}
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
public void hellofunction(View v)
{ mp.release();
mp=MediaPlayer.create(this, R.raw.helloworld);
mp.start();
}
}
剪辑片段.java ：
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class ClipsFragment extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.frag, container, false);
return rootView;
}
}
我做错了什么？如何解决此问题并使音频播放正常工作？
您
甚至在初始化之前就调用了 release mp
mp.release();
mp=MediaPlayer.create(this, R.raw.helloworld);
编辑：
在片段中
MediaPlayer mp;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.frag, container, false);
ImageView iv = (ImageView) rootView.findViewById(R.id.ImageView01);
iv.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
mp=MediaPlayer.create(getActivity(), R.raw.helloworld);
mp.start():
}
});
return rootView;
}
您可以删除android:onClick="hellofunction"