我的应用程序有问题，我是初学者，我想创建一个简单的应用程序，从项目中加载随机布局。它工作，但不正确，因为它在启动几次后工作，有时一打，然后它显示有关强制关闭的消息。这是来自eclipse的logCat。我应该更改什么来修复它并使其正常工作？我尝试了很多东西，但关键是我不知道问题出在哪里，这就是为什么我自己无法处理它。 ：
07-06 07:27:45.873: D/dalvikvm(220): GC freed 501 objects / 45848 bytes in 122ms
07-06 07:28:50.904: D/dalvikvm(220): GC freed 1436 objects / 65328 bytes in 85ms
07-06 07:28:55.703: D/AndroidRuntime(220): Shutting down VM
07-06 07:28:55.703: W/dalvikvm(220): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
07-06 07:28:55.703: E/AndroidRuntime(220): Uncaught handler: thread main exiting due to uncaught exception
07-06 07:28:55.724: E/AndroidRuntime(220): java.lang.RuntimeException: Unable to start activity ComponentInfo{ka.ka.ka/ka.ka.ka.RANDOMActivity}: java.lang.NullPointerException
07-06 07:28:55.724: E/AndroidRuntime(220): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.os.Handler.dispatchMessage(Handler.java:99)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.os.Looper.loop(Looper.java:123)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.app.ActivityThread.main(ActivityThread.java:4363)
07-06 07:28:55.724: E/AndroidRuntime(220): at java.lang.reflect.Method.invokeNative(Native Method)
07-06 07:28:55.724: E/AndroidRuntime(220): at java.lang.reflect.Method.invoke(Method.java:521)
07-06 07:28:55.724: E/AndroidRuntime(220): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
07-06 07:28:55.724: E/AndroidRuntime(220): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
07-06 07:28:55.724: E/AndroidRuntime(220): at dalvik.system.NativeStart.main(Native Method)
07-06 07:28:55.724: E/AndroidRuntime(220): Caused by: java.lang.NullPointerException
07-06 07:28:55.724: E/AndroidRuntime(220): at ka.ka.ka.RANDOMActivity.onCreate(RANDOMActivity.java:29)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
07-06 07:28:55.724: E/AndroidRuntime(220): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
07-06 07:28:55.724: E/AndroidRuntime(220): ... 11 more
07-06 07:28:55.754: I/dalvikvm(220): threadid=7: reacting to signal 3
07-06 07:28:55.754: E/dalvikvm(220): Unable to open stack trace file '/data/anr/traces.txt': Permission denied
07-06 07:28:57.283: I/Process(220): Sending signal. PID: 220 SIG: 9
这是我的代码：
KAMASAcctivity：
package ka.ka.ka;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class KAMASActivity extends Activity implements OnClickListener {
Button button1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button1 = (Button) findViewById(R.id.button1) ;
button1.setOnClickListener(this);
}
@Override
public void onClick(View v) {
startActivity(new Intent(getApplicationContext(), RANDOMActivity.class));
this.finish();
}
}
RANDOMActivity：
package ka.ka.ka;
import java.util.Random;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class RANDOMActivity extends Activity implements OnClickListener {
Button button1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
int min = 1;
int max = 4;
int i1=0;
Random r = new Random();
i1 = r.nextInt(max - min + 1) + min;
if(i1==1){setContentView(R.layout.image1);}
if(i1==2){setContentView(R.layout.image2);}
if(i1==3){setContentView(R.layout.image3);}
if(i1==4){setContentView(R.layout.image4);}
button1 = (Button) findViewById(R.id.button1) ;
button1.setOnClickListener(this);
}
@Override
public void onClick(View v) {
startActivity(new Intent(getApplicationContext(), RANDOM1Activity.class));
finish();
}
}
RANDOM1Activity：
package ka.ka.ka;
import java.util.Random;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class RANDOM1Activity extends Activity implements OnClickListener {
Button button1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
int min = 1;
int max = 4;
int i1=0;
Random r = new Random();
i1 = r.nextInt(max - min + 1) + min;
if(i1==1){setContentView(R.layout.image1);}
if(i1==2){setContentView(R.layout.image2);}
if(i1==3){setContentView(R.layout.image3);}
if(i1==4){setContentView(R.layout.image4);}
button1 = (Button) findViewById(R.id.button1) ;
button1.setOnClickListener(this);
}
@Override
public void onClick(View v) {
startActivity(new Intent(getApplicationContext(), RANDOMActivity.class));
finish();
}
}
答案 0 :(得分：1)
In your RANDOMActivity suppose if i1 value is not any of the given numbers from 1 to 4, then your activity will not have setContentView(). So you can put an else block to the if conditions and give a default setContentView() like this.
Random r = new Random();
i1 = r.nextInt(max - min + 1) + min;
if(i1==1){setContentView(R.layout.image1);}
else if(i1==2){setContentView(R.layout.image2);}
else if(i1==3){setContentView(R.layout.image3);}
else if(i1==4){setContentView(R.layout.image4);}
else {
setContentView(R.layout.image4);
}
答案 1 :(得分：0)
从LogCat看到这一行：
Unable to open stack trace file '/data/anr/traces.txt': Permission denied
这意味着您尝试访问traces.txt而未声明AndroidManifest.file中的 READ 权限。