Absichtsfehler: Wenn ich auf die Schaltfläche

Question

geklickt habe, versuche ich eine andere Aktivität mit Intent aufzurufen. Aber wenn ich auf den Button activityMain.xml klicke, stürzt es ab. Können Sie herausfinden, was das Problem ist?

MainActivity.java

package com.example.hacback17.framelayout; 

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.ImageView; 

public class MainActivity extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
    } 

    private void doSomething(View v) { 
     Intent intent = new Intent(MainActivity.this, NewActivity.class); 
     startActivity(intent); 

    } 
} 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    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="com.example.hacback17.framelayout.MainActivity"> 

    <Button 

     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Click Here" 
     android:onClick="doSomething"/> 
</RelativeLayout> 

NewActivity.java

package com.example.hacback17.framelayout; 

import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.view.View; 
import android.widget.Button; 
import android.widget.ImageView; 

/** 
* Created by Bablu on 7/5/2016. 
*/ 
public class NewActivity extends AppCompatActivity { 
    ImageView img1; 
    ImageView img2; 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.new_layout); 
    } 
} 

new_layout.xml

<?xml version="1.0" encoding="utf-8"?> 
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 


    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Hello"/> 

</FrameLayout> 

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.hacback17.framelayout"> 

    <application 
     android:allowBackup="true" 
     android:icon="@mipmap/ic_launcher" 
     android:label="@string/app_name" 
     android:supportsRtl="true" 
     android:theme="@style/AppTheme"> 
     <activity android:name=".MainActivity"> 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 

     <activity android:name=".NewActivity" 
      android:label="New Activity"> 
     </activity> 

    </application> 

</manifest> 

Logcat

Process: com.example.hacback17.framelayout, PID: 30567 
                        java.lang.IllegalStateException: Could not find method doSomething(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton 
                         at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:321) 
                         at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:280) 
                         at android.view.View.performClick(View.java:4444) 
                         at android.view.View$PerformClick.run(View.java:18457) 
                         at android.os.Handler.handleCallback(Handler.java:733) 
                         at android.os.Handler.dispatchMessage(Handler.java:95) 
                         at android.os.Looper.loop(Looper.java:136) 
                         at android.app.ActivityThread.main(ActivityThread.java:5113) 
                         at java.lang.reflect.Method.invokeNative(Native Method) 
                         at java.lang.reflect.Method.invoke(Method.java:515) 
                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609) 
                         at dalvik.system.NativeStart.main(Native Method) 

Answer 1

onClick Ereignis sollte öffentlich deklariert werden. Ersetzen Sie doSomething() -Methode Erklärung mit diesem:

public void doSomething(View v) { 
     Intent intent = new Intent(MainActivity.this, NewActivity.class); 
     startActivity(intent); 

    } 

Answer 2

Wenn Sie onclick xml verwenden möchten, sollte das Verfahren public sein.

Answer 3

ersetzen private void doSomething(View v) mit public void doSomething(View v)

Answer 4

oder u kann (id) auf Schaltfläche hinzufügen und kann dann als Taste = new Button findViewById (R.id.button); und dann kann Button.setOnclickListner (neue ON clickListner)