Question

我是android编程新手。当我点击＆＃34;打开第二个活动＆＃34; /＆＃34;打开第三个活动＆＃34;时，我开始使用多个活动并运行应用程序。按钮，Genymotion模拟器说：不幸的是，FirstApp已停止。并返回到android菜单..为什么？我收到这样的错误

java.lang.IllegalStateException: Could not execute method of the activity
  at android.view.View$1.onClick(View.java:4020)
  at android.view.View.performClick(View.java:4780)
  at android.view.View$PerformClick.run(View.java:19866)
  at android.os.Handler.handleCallback(Handler.java:739)
  at android.os.Handler.dispatchMessage(Handler.java:95)
  at android.os.Looper.loop(Looper.java:135)
  at android.app.ActivityThread.main(ActivityThread.java:5257)
  at java.lang.reflect.Method.invoke(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:372)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.reflect.InvocationTargetException
  at java.lang.reflect.Method.invoke(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:372)
  at android.view.View$1.onClick(View.java:4015)
  at android.view.View.performClick(View.java:4780) 
  at android.view.View$PerformClick.run(View.java:19866) 
  at android.os.Handler.handleCallback(Handler.java:739) 
  at android.os.Handler.dispatchMessage(Handler.java:95) 
  at android.os.Looper.loop(Looper.java:135) 
  at android.app.ActivityThread.main(ActivityThread.java:5257) 
  at java.lang.reflect.Method.invoke(Native Method) 
  at java.lang.reflect.Method.invoke(Method.java:372) 
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.jahnaviswaroop11gmail.firstapp/com.jahnaviswaroop11gmail.firstapp.SecondActivity}; have you declared this activity in your AndroidManifest.xml?
  at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1777)
  at android.app.Instrumentation.execStartActivity(Instrumentation.java:1501)
  at android.app.Activity.startActivityForResult(Activity.java:3745)
  at android.app.Activity.startActivityForResult(Activity.java:3706)
  at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:820)
  at android.app.Activity.startActivity(Activity.java:4016)
  at android.app.Activity.startActivity(Activity.java:3984)
  at com.jahnaviswaroop11gmail.firstapp.FirstActivity.showGreetings(FirstActivity.java:25)
  at java.lang.reflect.Method.invoke(Native Method) 
  at java.lang.reflect.Method.invoke(Method.java:372) 
  at android.view.View$1.onClick(View.java:4015) 
  at android.view.View.performClick(View.java:4780) 
  at android.view.View$PerformClick.run(View.java:19866) 
  at android.os.Handler.handleCallback(Handler.java:739) 
  at android.os.Handler.dispatchMessage(Handler.java:95) 
  at android.os.Looper.loop(Looper.java:135) 
  at android.app.ActivityThread.main(ActivityThread.java:5257) 
  at java.lang.reflect.Method.invoke(Native Method) 
  at java.lang.reflect.Method.invoke(Method.java:372) 
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

我的FirstActivity.java

public class FirstActivity extends AppCompatActivity {
    TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
        textView = (TextView) findViewById(R.id.greetings_text_view);
    }
    public void showGreetings(View view){
       String button_text = ( (Button)  view).getText().toString();
        if (button_text.equals("Open Second Activity"))
        {
            Intent intent = new Intent(this,SecondActivity.class);

            startActivity(intent);
        }

        else if (button_text.equals("Open Third Activity"))
        {
            Intent intent = new Intent(this,ThirdActivity.class);
            startActivity(intent);

        }
    }

}

我的SecondActvity.java

import android.app.Activity;
import android.os.Bundle;

public class SecondActivity extends Activity {
@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second_layout);
    }
}

我的ThirdActivity.java

import android.app.Activity;
import android.os.Bundle;

public class ThirdActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.third_layout);

    }
}

我的firstlayout.xml文件

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="greetings appear here"
android:id="@+id/greetings_text_view"/>
<Button
    android:layout_width="match_parent"
    android:layout_height="wrap_content"

    android:text="Open Second Activity"
    android:onClick="showGreetings"
    android:layout_below="@+id/greetings_text_view"

    android:id="@+id/button" />

<Button
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Open Third Activity"
    android:onClick="showGreetings"
    android:id="@+id/button2"
    android:layout_below="@+id/button"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="71dp" />

我的第二个xml文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Welcome to Second Activity"
    android:id="@+id/textView"
    android:layout_gravity="center_horizontal" />

我的第三个布局xml文件

 <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Welcome to third Activity"
    android:id="@+id/textView2"
    android:layout_gravity="center_horizontal" />

Answer 1

请在发布问题之前验证异常堆栈跟踪。例外情况清楚地提到了问题的原因..

Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.jahnaviswaroop11gmail.firstapp/com.jahnaviswaroop11gmail.firstapp.SecondActivity}; have you declared this activity in your AndroidManifest.xml?

将SecondActvity添加到<application>代码

内的AndroidManifest.xml中

<activity android:name="com.jahnaviswaroop11gmail.firstapp.SecondActivity" />

Answer 2

将其添加到<application>标记内的清单中。它应该可以解决你的问题。

<activity android:name="com.jahnaviswaroop11gmail.firstapp.SecondActivity"/>

Answer 3

Androidmanifest.xml包含不正确的数据，您必须添加有关第二和第三项活动的信息

    <activity 
        android:name=".SecondActivity"/>
    <activity
        android:name=".ThirdActivity"/>

Answer 4

您需要将第一个和第二个活动都放到您的清单......

<activity android:name=".SecondActivity"/>

<activity android:name=".ThirdActivity"/>

并获得文字

Button button = (Button)view;

String button_text= button.getText().toString();

并添加权限

 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

活动无效

4 个答案: