在Android中開始新的活動錯誤

Question

我正在嘗試一個非常簡單的示例。我有兩個活動，一個是蘋果課，一個是燻肉課。我正在使用蘋果類上的按鈕來打開燻肉課活動。

的代碼是蘋果類如下：

package jdexamples.app12_intent; 

import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.content.Intent; 
import android.view.View; 

public class Apples extends AppCompatActivity { 

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

    public void onClick(){ 
     Intent i = new Intent(this, Bacon.class); 
     startActivity(i); 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_apples, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 
} 

的XML爲蘋果類看起來如下：

<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:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".Apples" 
    android:background="#00FF00"> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="?android:attr/textAppearanceLarge" 
     android:text="@string/applesText" 
     android:id="@+id/applesText" 
     android:layout_alignParentTop="true" 
     android:layout_centerHorizontal="true" 
     android:layout_marginTop="29dp" /> 

    <Button 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/applesButton" 
     android:id="@+id/applesButton" 
     android:layout_below="@+id/applesText" 
     android:layout_centerHorizontal="true" 
     android:layout_marginTop="51dp" 
     android:onClick="onClick" 
     android:nestedScrollingEnabled="false" /> 
</RelativeLayout> 

每當我打開模擬器它顯示了類似以下但當我按下按鈕程序崩潰：不知道這裏發生了什麼。

Answer 1

這應該是像

public void onClick(View v){ 

您需要通過View的論點onClick(...)

Answer 2

請在您的佈局改變以下線

android:onClick="onClickButton" 

下面做改變你的java clas s，

public void onClickButton(View V){ 
     Intent i = new Intent(this, Bacon.class); 
     startActivity(i); 
    } 

因爲onClick會覆蓋方法，所以這是更改名稱的原因。

Answer 3

試試這個：

public void onClickButton(View v){ 
    Intent i = new Intent(this, Bacon.class); 
    startActivity(i); 
} 

Answer 4

package jdexamples.app12_intent; 

import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.content.Intent; 
import android.view.View; 

public class Apples extends AppCompatActivity { 

    Button send; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_apples); 
     send = (Button)findViewById(R.id.applesButton); 
     send.setOnClickListener(new OnClickListener() { 
     @Override 
      public void onClick(View v) { 
       Intent i = new Intent(this, Bacon.class); 
       startActivity(i); 
      } 
     @Override 
     `enter code here`public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_apples, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 
}