问题描述
对所有人来说，我试图在android中创建绘画活动，但是它显示了打开绘画活动时的错误。我不知道什么是解决此问题的正确方法。我希望这个堆栈溢出的社区能够帮助我解决此问题。谢谢
请帮助我，以便我可以在ANDROID中创建绘画活动
activity_paint.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/activity_color"
android:fitsSystemWindows="true"
android:theme="@style/ThemeOverlay.AppCompat.Dark"
tools:context=".PaintActivity">
<com.app.drawing.Util.CanvasView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/ThemeOverlay.AppCompat.Dark"
app:layout_constraintTop_toTopOf="parent">
</com.app.drawing.Util.CanvasView>
<include layout="@layout/content_main" />
</androidx.constraintlayout.widget.ConstraintLayout>
content_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<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>
<com.google.android.material.appbar.AppBarLayout
android:id="@+id/drawing"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#FFFFFFFF" />
<!-- Top Row -->
<LinearLayout
android:id="@+id/paint_colors"
android:layout_gravity="center"
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="2dp"
android:background="#FF660000"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FF660000" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FFFF0000"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FFFF0000" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FFFF6600"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FFFF6600" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FFFFCC00"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FFFFCC00" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FF009900"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FF009900" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FF009999"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FF009999" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FF0000FF"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FF0000FF" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FF990099"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FF990099" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FFFF6666"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FFFF6666" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FFFFFFFF"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FFFFFFFF" />
<ImageButton
android:layout_width="@dimen/large_brush"
android:layout_height="@dimen/large_brush"
android:layout_margin="2dp"
android:background="#FF787878"
android:contentDescription="@string/paint"
android:onClick="paintClicked"
android:src="@drawable/paint"
android:tag="#FF787878" />
</LinearLayout>
</LinearLayout>
PaintActivity.java
package com.example.learnbest_kidsapp;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import java.util.UUID;
public class PaintActivity extends AppCompatActivity implements OnClickListener{
private ImageButton currPaint,drawBtn,baru,erase,save;
private DrawingView drawView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_paint);
//=======================this is the 31 line========================================
drawView = (DrawingView)findViewById(R.id.drawing);
//=======================this is the 31 line========================================
drawBtn = (ImageButton)findViewById(R.id.draw_btn);
baru = (ImageButton)findViewById(R.id.new_btn);
erase = (ImageButton)findViewById(R.id.erase_btn);
save = (ImageButton)findViewById(R.id.save_btn);
LinearLayout paintLayout = (LinearLayout)findViewById(R.id.paint_colors);
currPaint = (ImageButton)paintLayout.getChildAt(0);
currPaint.setImageDrawable(getResources().getDrawable(R.drawable.paint_pressed));
drawBtn.setOnClickListener(this);
baru.setOnClickListener(this);
erase.setOnClickListener(this);
save.setOnClickListener(this);
}
public void paintClicked(View view){
if(view!=currPaint){
ImageButton imgView = (ImageButton)view;
String color = view.getTag().toString();
drawView.setColor(color);
imgView.setImageDrawable(getResources().getDrawable(R.drawable.paint_pressed));
currPaint.setImageDrawable(getResources().getDrawable(R.drawable.paint));
currPaint=(ImageButton)view;
}
}
@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_main,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);
}
@Override
public void onClick(View v) {
if(v.getId()==R.id.draw_btn){
drawView.setupDrawing();
}
if(v.getId()==R.id.erase_btn){
drawView.setErase(true);
drawView.setBrushSize(drawView.getLastBrushSize());
}
if(v.getId()==R.id.new_btn){
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("No",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
dialog.cancel();
}
});
newDialog.show();
}
if(v.getId()==R.id.save_btn){
AlertDialog.Builder saveDialog = new AlertDialog.Builder(this);
saveDialog.setTitle("Save drawing");
saveDialog.setMessage("Save drawing to device Gallery?");
saveDialog.setPositiveButton("Yes",int which){
drawView.setDrawingCacheEnabled(true);
String imgSaved = MediaStore.Images.Media.insertImage(
getContentResolver(),drawView.getDrawingCache(),UUID.randomUUID().toString()+".png","drawing");
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("No",int which){
dialog.cancel();
}
});
saveDialog.show();
}
}
}
错误
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.learnbest_kidsapp,PID: 19987
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.learnbest_kidsapp/com.example.learnbest_kidsapp.PaintActivity}: java.lang.ClassCastException: com.google.android.material.appbar.AppBarLayout cannot be cast to com.example.learnbest_kidsapp.DrawingView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.ClassCastException: com.google.android.material.appbar.AppBarLayout cannot be cast to com.example.learnbest_kidsapp.DrawingView
at com.example.learnbest_kidsapp.PaintActivity.onCreate(PaintActivity.java:31)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
I/Process: Sending signal. PID: 19987 SIG: 9
Process 19987 terminated.
解决方法
暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！
如果你已经找到好的解决方法，欢迎将解决方案带上本链接一起发送给小编。
小编邮箱:dio#foxmail.com (将#修改为@）