我正在尝试在该类的另一个类中创建一个动态按钮，Penicillins.class但出现此错误
私人最终活动 performLaunchActivity(ActivityRecord r) {
// System.out.println("##### [" + System.currentTimeMillis() + "] ActivityThread.performLaunchActivity(" + r + ")");
ActivityInfo aInfo = r.activityInfo;
if (r.packageInfo == null) {
r.packageInfo = getPackageInfo(aInfo.applicationInfo,
Context.CONTEXT_INCLUDE_CODE);
}
ComponentName component = r.intent.getComponent();
if (component == null) {
component = r.intent.resolveActivity(
mInitialApplication.getPackageManager());
r.intent.setComponent(component);
}
if (r.activityInfo.targetActivity != null) {
component = new ComponentName(r.activityInfo.packageName,
r.activityInfo.targetActivity);
}
Activity activity = null;
try {
java.lang.ClassLoader cl = r.packageInfo.getClassLoader();
activity = mInstrumentation.newActivity(
cl, component.getClassName(), r.intent);
r.intent.setExtrasClassLoader(cl);
if (r.state != null) {
r.state.setClassLoader(cl);
这是具有创建新按钮的按钮的java：
package org.iimed.www;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import org.iimed.www.Sundayopen;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.drawable.Drawable;
public class Penicillins extends Activity implements OnClickListener{
ImageButton back,addmed;
Context adaba;
Drawable mmimed;
Button button;
RelativeLayout rl;
public void onCreate(Bundle SavedInstanceState){
super.onCreate(SavedInstanceState);
setContentView(R.layout.penicillin);
rl = (RelativeLayout)findViewById(R.id.sundayopen);
back = (ImageButton) findViewById(R.id.back);
addmed = (ImageButton) findViewById(R.id.addmed);
back.setOnClickListener(this);
addmed.setOnClickListener(this);
}
ImageButton addmed = (ImageButton) findViewById(R.id.addmed);
public void onClick(View v) {
LayoutParams b = new LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
Button button = new Button(this);
button.setText("hello");
button.setLayoutParams(b);
rl.addView(button);
}}
记录猫错误
01-08 22:10:52.505: E/AndroidRuntime(14353): FATAL EXCEPTION: main
01-08 22:10:52.505: E/AndroidRuntime(14353): java.lang.RuntimeException: Unable to instantiate application android.app.Application: java.lang.NullPointerException
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.LoadedApk.makeApplication(LoadedApk.java:516)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4568)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.ActivityThread.access$1400(ActivityThread.java:152)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1342)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.os.Handler.dispatchMessage(Handler.java:99)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.os.Looper.loop(Looper.java:137)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.ActivityThread.main(ActivityThread.java:5328)
01-08 22:10:52.505: E/AndroidRuntime(14353): at java.lang.reflect.Method.invokeNative(Native Method)
01-08 22:10:52.505: E/AndroidRuntime(14353): at java.lang.reflect.Method.invoke(Method.java:511)
01-08 22:10:52.505: E/AndroidRuntime(14353): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
01-08 22:10:52.505: E/AndroidRuntime(14353): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
01-08 22:10:52.505: E/AndroidRuntime(14353): at dalvik.system.NativeStart.main(Native Method)
01-08 22:10:52.505: E/AndroidRuntime(14353): Caused by: java.lang.NullPointerException
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.LoadedApk.initializeJavaContextClassLoader(LoadedApk.java:387)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.LoadedApk.getClassLoader(LoadedApk.java:325)
01-08 22:10:52.505: E/AndroidRuntime(14353): at android.app.LoadedApk.makeApplication(LoadedApk.java:504)
01-08 22:10:52.505: E/AndroidRuntime(14353): ... 11 more
也堆叠
ActivityThread.performLaunchActivity(ActivityThread$ActivityClientRecord, Intent) line: 2173
ActivityThread.handleLaunchActivity(ActivityThread$ActivityClientRecord, Intent) line: 2297
ActivityThread.access$700(ActivityThread, ActivityThread$ActivityClientRecord, Intent) line: 152
ActivityThread$H.handleMessage(Message) line: 1282
ActivityThread$H(Handler).dispatchMessage(Message) line: 99
Looper.loop() line: 137
ActivityThread.main(String[]) line: 5328
Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]
Method.invoke(Object, Object...) line: 511
ZygoteInit$MethodAndArgsCaller.run() line: 1102
ZygoteInit.main(String[]) line: 869
NativeStart.main(String[]) line: not available [native method]
我认为问题可能是我的目录因剪切粘贴一些东西而变得很糟糕，因为 sdk 管理器现在告诉我我没有安装所有正确的平台工具，现在下载它们。