添加ImageView时应用程序崩溃

Question

I'm trying to add an image to my app but it keeps crashing and I can't conclude why.

I have multiple images in my app, but adding this one image seems to be problematic. Here's my xml (EDIT: full xml (This has changed since the original for layout purposes)):

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="match_parent" >

<Button
    android:id="@+id/imageTextButton4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/imageTextButton3"
    android:layout_alignBottom="@+id/imageTextButton3"
    android:layout_alignLeft="@+id/imageTextButton2"
    android:layout_alignRight="@+id/imageTextButton2"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Progress" />

<Button
    android:id="@+id/imageTextButton3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/imageTextButton1"
    android:layout_alignRight="@+id/imageTextButton1"
    android:layout_below="@+id/imageTextButton1"
    android:layout_marginTop="85dp"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Meal Plans" />

<Button
    android:id="@+id/imageTextButton2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    android:layout_marginRight="22dp"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Your Meals" />

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="42dp"
    android:src="@drawable/logo" />

<Button
    android:id="@+id/imageTextButton1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_centerVertical="true"
    android:layout_marginLeft="16dp"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Meal of the Day" />

</RelativeLayout>

And my java code (condensed for brevity):

package com.example.c3347115app;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.content.Intent;

public class MainActivity extends Activity {

ImageView image;

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

    image = (ImageView) findViewById(R.id.imageView1);

Logcat:

05-10 01:55:30.718: W/dalvikvm(13140): threadid=1: thread exiting with uncaught exception (group=0x40a99228)
05-10 01:55:30.728: E/AndroidRuntime(13140): FATAL EXCEPTION: main
05-10 01:55:30.728: E/AndroidRuntime(13140): java.lang.RuntimeException: Unable to     start activity ComponentInfo{com.example.c3347115app/com.example.c3347115app.MainActivity}: java.lang.ClassCastException: android.widget.Button cannot be cast to android.widget.ImageView
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2205)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2240)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.app.ActivityThread.access$600(ActivityThread.java:139)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1262)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.os.Looper.loop(Looper.java:156)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.app.ActivityThread.main(ActivityThread.java:4987)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at java.lang.reflect.Method.invokeNative(Native Method)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at java.lang.reflect.Method.invoke(Method.java:511)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at dalvik.system.NativeStart.main(Native Method)
05-10 01:55:30.728: E/AndroidRuntime(13140): Caused by: java.lang.ClassCastException:      android.widget.Button cannot be cast to android.widget.ImageView
05-10 01:55:30.728: E/AndroidRuntime(13140):    at com.example.c3347115app.MainActivity.onCreate(MainActivity.java:22)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.app.Activity.performCreate(Activity.java:4538)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071)
05-10 01:55:30.728: E/AndroidRuntime(13140):    at        android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2161)

Can anyone figure out what the problem is? Thanks in advance.

Answer 1

These two lines look problematic to me:

android:layout_above="@+id/imageTextButton1"
android:layout_alignRight="@+id/imageTextButton2"

Doesn't the "@+id/" form generate a new id value? Perhaps you meant "@id/"

Answer 2

When crating ids in xml file (using @+id/) You do it just on first occurrence and later You use just @id/

So Your xml should look like this

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="match_parent" >

<Button
    android:id="@+id/imageTextButton4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/imageTextButton3"
    android:layout_alignBottom="@id/imageTextButton3"
    android:layout_alignLeft="@+id/imageTextButton2"
    android:layout_alignRight="@id/imageTextButton2"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Progress" />

<Button
    android:id="@id/imageTextButton3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/imageTextButton1"
    android:layout_alignRight="@id/imageTextButton1"
    android:layout_below="@id/imageTextButton1"
    android:layout_marginTop="85dp"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Meal Plans" />

<Button
    android:id="@id/imageTextButton2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    android:layout_marginRight="22dp"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Your Meals" />

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="42dp"
    android:src="@drawable/logo" />

<Button
    android:id="@id/imageTextButton1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_centerVertical="true"
    android:layout_marginLeft="16dp"
    android:drawableTop="@drawable/ic_launcher"
    android:text="Meal of the Day" />

</RelativeLayout>

Answer 3

Caused by: java.lang.ClassCastException: android.widget.Button cannot be cast to android.widget.ImageView

You seem to have a Button in your layout with the same ID as your ImageView

Answer 4

I just found out what used to go wrong when i added an image. The problem is, in my case, that ScrollView can't have more than one direct child. So when i added an image side by side to the existing child, the compile shows no errors but the runtime application crashes on create. The solution was to add a layout inside the scrollview as a unique direct child, inside which will go my usefull scrollview content layouts and views.