当我尝试在底部线性布局的表格之外添加图像按钮时，我的绘图应用程序在启动时崩溃。谁能指出我正确的方向？
XML:
<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">
<com.sothree.slidinguppanel.SlidingUpPanelLayout
android:id="@+id/sliding_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true">
<LinearLayout
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FFCCCCCC"
android:orientation="vertical"
tools:context=".MainActivity" >
<!-- Top Buttons -->
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_gravity="center"
android:orientation="horizontal" >
<ImageButton
android:id="@+id/new_btn"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:contentDescription="@string/start_new"
android:src="@drawable/new_pic" />
<ImageButton
android:id="@+id/draw_btn"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:contentDescription="@string/brush"
android:src="@drawable/brush" />
<ImageButton
android:id="@+id/erase_btn"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:contentDescription="@string/erase"
android:src="@drawable/eraser" />
<ImageButton
android:id="@+id/save_btn"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:contentDescription="@string/save"
android:src="@drawable/save" />
</LinearLayout>
<!-- Custom View -->
<com.example.drawingfun.DrawingView
android:id="@+id/drawing"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_marginBottom="3dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="3dp"
android:layout_weight="1"
android:background="#FFFFFFFF"
android:scaleType="centerInside" />
</LinearLayout>
<!-- Color Palette -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:orientation="vertical"
android:clickable="true">
<!-- Top Row -->
<TableLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<TableRow>
<LinearLayout
android:id="@+id/paint_colors"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background = "@drawable/colorbutton1"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton1"
android:tag="#FFE21A1A" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton2"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton2"
android:tag="#FFF2D820" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton3"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton3"
android:tag="#FF35EF22" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton4"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton4"
android:tag="#FF26D3EA" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton5"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton5"
android:tag="#FFF73E9B" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton6"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton6"
android:tag="#FFFFFFFF" />
</LinearLayout>
</TableRow>
<!-- Bottom Row -->
<TableRow>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton7"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton7"
android:tag="#FF7A4426"/>
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton8"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton8"
android:tag="#FFF74F1C"/>
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton9"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton9"
android:tag="#FF217C14" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton10"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton10"
android:tag="#FF312EBC"/>
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton11"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton11"
android:tag="#FF5D1F93" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="4dp"
android:background="@drawable/colorbutton12"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/colorbutton12"
android:tag="#FF000000"/>
</LinearLayout>
</TableRow>
</TableLayout>
<ImageButton
android:id="@+id/botDrag"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="8dp"
android:gravity="center_horizontal"
android:background = "@drawable/sendbutton"
android:contentDescription="@string/drag"
android:src="@drawable/sendbutton"
android:tag="#FFE21A1A" />
</LinearLayout>
</com.sothree.slidinguppanel.SlidingUpPanelLayout>
</RelativeLayout>
爪哇：
package com.example.drawingfun;
import java.util.UUID;
import android.os.Bundle;
import android.provider.MediaStore;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TableRow;
import android.widget.TableLayout;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.Toast;
import com.sothree.slidinguppanel.SlidingUpPanelLayout;
import com.sothree.slidinguppanel.SlidingUpPanelLayout.PanelSlideListener;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
/**
* This is demo code to accompany the Mobiletuts+ tutorial series:
* - Android SDK: Create a Drawing App
*
* Sue Smith
* August 2013
*
*/
public class MainActivity extends Activity implements OnClickListener {
//custom drawing view
private DrawingView drawView;
private View botDrag;
//buttons
private ImageButton currPaint, drawBtn, eraseBtn, newBtn, saveBtn;
//sizes
private float mediumBrush;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//get drawing view
drawView = (DrawingView)findViewById(R.id.drawing);
//get bottom panel drag view
botDrag = (View)findViewById(R.id.botDrag);
//get the palette and first color button
LinearLayout paintLayout = (LinearLayout)findViewById(R.id.paint_colors);
currPaint = (ImageButton)paintLayout.getChildAt(0);
currPaint.setImageDrawable(getResources().getDrawable(R.drawable.paint_pressed));
//Send current brush size to color palette
//sizes from dimensions
mediumBrush = getResources().getInteger(R.integer.medium_size);
//draw button
drawBtn = (ImageButton)findViewById(R.id.draw_btn);
drawBtn.setOnClickListener(this);
//set initial size
drawView.setBrushSize(mediumBrush);
//erase button
eraseBtn = (ImageButton)findViewById(R.id.erase_btn);
eraseBtn.setOnClickListener(this);
//new button
newBtn = (ImageButton)findViewById(R.id.new_btn);
newBtn.setOnClickListener(this);
//save button
saveBtn = (ImageButton)findViewById(R.id.save_btn);
saveBtn.setOnClickListener(this);
SlidingUpPanelLayout layout = (SlidingUpPanelLayout) findViewById(R.id.sliding_layout);
layout.setShadowDrawable(getResources().getDrawable(R.drawable.above_shadow));
layout.setAnchorPoint(0.3f);
layout.setDragView(botDrag);
layout.setPanelSlideListener(new PanelSlideListener() {
@Override
public void onPanelSlide(View panel, float slideOffset) {
if (slideOffset < 0.2) {
if (getActionBar().isShowing()) {
getActionBar().hide();
}
} else {
if (!getActionBar().isShowing()) {
getActionBar().show();
}
}
}
@Override
public void onPanelExpanded(View panel) {
}
@Override
public void onPanelCollapsed(View panel) {
}
@Override
public void onPanelAnchored(View panel) {
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
//user clicked paint
public void paintClicked(View view){
//use chosen color
//set erase false
drawView.setErase(false);
drawView.setBrushSize(drawView.getLastBrushSize());
if(view!=currPaint){
ImageButton imgView = (ImageButton)view;
String color = view.getTag().toString();
drawView.setColor(color);
//update ui
imgView.setImageDrawable(getResources().getDrawable(R.drawable.paint_pressed));
currPaint.setImageDrawable(getResources().getDrawable(R.drawable.paint));
currPaint=(ImageButton)view;
}
}
@Override
public void onClick(View view){
if(view.getId()==R.id.draw_btn){
//draw button clicked
final Dialog brushDialog = new Dialog(this);
brushDialog.setTitle("Brush size:");
brushDialog.setContentView(R.layout.brush_seekbar);
brushDialog.setCancelable(true);
SeekBar brushSeekbar = (SeekBar) brushDialog.findViewById(R.id.brushSize_seekbar);
int brushSize = brushSeekbar.getProgress();
brushSeekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
if (fromUser)
drawView.setErase(false); //turn off eraser
drawView.setBrushSize(progress); //Change StrokeWidth
}
});
Button closeBrushBtn = (Button) brushDialog.findViewById(R.id.closeBrushBtn);
// if decline button is clicked, close the custom dialog
closeBrushBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// Close dialog
brushDialog.dismiss();
}
});
brushDialog.show();
//pass brush size to DrawingView
}
else if(view.getId()==R.id.erase_btn){
//switch to erase - choose size
final Dialog brushDialog = new Dialog(this);
brushDialog.setTitle("Erase size:");
brushDialog.setContentView(R.layout.brush_seekbar);
brushDialog.setCancelable(true);
SeekBar brushSeekbar = (SeekBar) brushDialog.findViewById(R.id.brushSize_seekbar);
brushSeekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
if (fromUser)
drawView.setErase(true);
drawView.setBrushSize(progress); //Change StrokeWidth
}
});
Button closeBrushBtn = (Button) brushDialog.findViewById(R.id.closeBrushBtn);
// if decline button is clicked, close the custom dialog
closeBrushBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// Close dialog
brushDialog.dismiss();
}
});
brushDialog.show();
}
else if(view.getId()==R.id.new_btn){
//new button
AlertDialog.Builder newDialog = new AlertDialog.Builder(this);
newDialog.setTitle("New drawing");
newDialog.setMessage("Start new drawing (you will lose the current drawing)?");
newDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
drawView.startNew();
dialog.dismiss();
}
});
newDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
dialog.cancel();
}
});
newDialog.show();
}
else if(view.getId()==R.id.save_btn){
//save drawing
AlertDialog.Builder saveDialog = new AlertDialog.Builder(this);
saveDialog.setTitle("Save drawing");
saveDialog.setMessage("Save drawing to device Gallery?");
saveDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
//save drawing
drawView.setDrawingCacheEnabled(true);
//attempt to save
String imgSaved = MediaStore.Images.Media.insertImage(
getContentResolver(), drawView.getDrawingCache(),
UUID.randomUUID().toString()+".png", "drawing");
//feedback
if(imgSaved!=null){
Toast savedToast = Toast.makeText(getApplicationContext(),
"Drawing saved to Gallery!", Toast.LENGTH_SHORT);
savedToast.show();
}
else{
Toast unsavedToast = Toast.makeText(getApplicationContext(),
"Oops! Image could not be saved.", Toast.LENGTH_SHORT);
unsavedToast.show();
}
drawView.destroyDrawingCache();
}
});
saveDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
dialog.cancel();
}
});
saveDialog.show();
}
}
}
日志猫：
10-26 20:55:10.716: E/AndroidRuntime(883): FATAL EXCEPTION: main
10-26 20:55:10.716: E/AndroidRuntime(883): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.drawingfun/com.example.drawingfun.MainActivity}: java.lang.ClassCastException: android.widget.TableRow cannot be cast to android.widget.ImageButton
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.ActivityThread.access$600(ActivityThread.java:141)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.os.Handler.dispatchMessage(Handler.java:99)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.os.Looper.loop(Looper.java:137)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.ActivityThread.main(ActivityThread.java:5103)
10-26 20:55:10.716: E/AndroidRuntime(883): at java.lang.reflect.Method.invokeNative(Native Method)
10-26 20:55:10.716: E/AndroidRuntime(883): at java.lang.reflect.Method.invoke(Method.java:525)
10-26 20:55:10.716: E/AndroidRuntime(883): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
10-26 20:55:10.716: E/AndroidRuntime(883): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-26 20:55:10.716: E/AndroidRuntime(883): at dalvik.system.NativeStart.main(Native Method)
10-26 20:55:10.716: E/AndroidRuntime(883): Caused by: java.lang.ClassCastException: android.widget.TableRow cannot be cast to android.widget.ImageButton
10-26 20:55:10.716: E/AndroidRuntime(883): at com.example.drawingfun.MainActivity.onCreate(MainActivity.java:53)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.Activity.performCreate(Activity.java:5133)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
10-26 20:55:10.716: E/AndroidRuntime(883): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
10-26 20:55:10.716: E/AndroidRuntime(883): ... 11 more
感谢您的帮助，我是 Android 开发的新手，在这里迷路了。