如何在android中清除视图？
我已经在android中创建了一个简单的绘图演示应用程序，现在有人能告诉我如何在一次点击中删除视图和清除屏幕。我已经尝试了以下方法：请帮助我做到这一点…thanx提前 main.java如何在android中清除视图？,android,android-canvas,android-view,Android,Android Canvas,Android View,我已经在android中创建了一个简单的绘图演示应用程序，现在有人能告诉我如何在一次点击中删除视图和清除屏幕。我已经尝试了以下方法：请帮助我做到这一点…thanx提前 main.java package com.example.singletouch; import com.example.singletouch.R.attr; import android.os.Bundle; import android.app.Activity; import android.graphics.Can
package com.example.singletouch;
import com.example.singletouch.R.attr;
import android.os.Bundle;
import android.app.Activity;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class MainActivity extends Activity {
ImageView pen;
SingleTouchView mDrawView;
ImageView remove;
LinearLayout pens;
LinearLayout pen1, pen2, pen3, pen4;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDrawView = (SingleTouchView) findViewById(R.id.myview);
pen = (ImageView) findViewById(R.id.pen);
pens = (LinearLayout) findViewById(R.id.linear);
pens.setVisibility(View.GONE);
pen1 = (LinearLayout) findViewById(R.id.pen1);
pen2 = (LinearLayout) findViewById(R.id.pen2);
pen3 = (LinearLayout) findViewById(R.id.pen3);
pen4 = (LinearLayout) findViewById(R.id.pen4);
remove=(ImageView)findViewById(R.id.remove);
/*
* pen1.setOnClickListener(this); pen2.setOnClickListener(this);
* pen3.setOnClickListener(this); pen4.setOnClickListener(this);
*/
pen.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
pens.setVisibility(View.VISIBLE);
}
});pens.setVisibility(View.GONE);
pen1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_1);
pens.setVisibility(View.GONE);
}
});
pen2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_2);
pens.setVisibility(View.GONE);
}
});
pen3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
pens.setVisibility(View.GONE);
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_3);
}
});
pen4.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
pens.setVisibility(View.GONE);
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_4);
}
});
remove.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
}
});
}
}
package com.example.singletouch;
import java.util.AbstractMap;
import java.util.Map;
import java.util.concurrent.ConcurrentLinkedQueue;
import android.R.color;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff.Mode;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.Switch;
public class SingleTouchView extends View{
public int width;
public int height;
public Bitmap mBitmap;
public Canvas mCanvas;
public Path mPath;
public Paint mBitmapPaint;
Context context;
public Paint circlePaint;
public Path circlePath;
public enum DrawingPens {
PEN_1(6),
PEN_2(4),
PEN_3(2),
PEN_4(1);
final public Paint mPaint;
/**
* Constructor
*
* @param width width of stroke
* @param color color of stroke
*/
private DrawingPens(final int width) {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(width);
//mPaint.setColor(color);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
}
/**
* @return corresponding paint
*/
Paint getPaint() {
return mPaint;
}
}
public SingleTouchView(final Context context) {
super(context);
init(context);
}
public SingleTouchView(final Context context, final AttributeSet attrs) {
super(context, attrs);
init(context);
}
public SingleTouchView(final Context context, final AttributeSet attrs, final int defStyle) {
super(context, attrs, defStyle);
init(context);
}
/** To store Paint - Path relation */
// TODO: depending on exact limits, more optimal ways can be found
private ConcurrentLinkedQueue<Map.Entry<Path, DrawingPens>> mPaths = new ConcurrentLinkedQueue<Map.Entry<Path, DrawingPens>>();
/** Cached current path, <b>NOTE:</b> this field is tail at mPaths and is used it only for caching, not drawing */
private Path mCurrentPath;
/**
* Inits internal views data, should be called from every constructor
*
* @param context {@link Context}
*/
private void init(final Context context) {
/* TODO: if some values of paints cannot be determined in static context (in enum),
then Paints should be created here and used via EnumMap */
// Initial pen
setPen(DrawingPens.PEN_1);
}
@Override
public void onDraw(Canvas canvas){
// just to draw background
super.onDraw(canvas);
// Draw all paths
for (Map.Entry<Path, DrawingPens> entry : mPaths) {
canvas.drawPath(entry.getKey(), entry.getValue().getPaint());
}
}
@Override
public boolean onTouchEvent(MotionEvent me){
float eventX = me.getX();
float eventY = me.getY();
switch (me.getAction()) {
case MotionEvent.ACTION_DOWN:
mCurrentPath.moveTo(eventX, eventY);
return true;
case MotionEvent.ACTION_MOVE:
mCurrentPath.lineTo(eventX, eventY);
break;
case MotionEvent.ACTION_UP:
break;
}
invalidate();
return true;
}
/**
* Setter for new pen
*
* @param pen {@link DrawingPens} to be used for next drawing
*/
public void setPen(final DrawingPens pen) {
// put latest item to the queue
mCurrentPath = new Path();
mPaths.add(new AbstractMap.SimpleImmutableEntry<Path, DrawingPens>(mCurrentPath, pen));
}
public void clear(View v){
}
}
package com.example.singletouch;
import com.example.singletouch.R.attr;
import android.os.Bundle;
import android.app.Activity;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class MainActivity extends Activity {
ImageView pen;
SingleTouchView mDrawView;
ImageView remove;
LinearLayout pens;
LinearLayout pen1, pen2, pen3, pen4;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDrawView = (SingleTouchView) findViewById(R.id.myview);
pen = (ImageView) findViewById(R.id.pen);
pens = (LinearLayout) findViewById(R.id.linear);
pens.setVisibility(View.GONE);
pen1 = (LinearLayout) findViewById(R.id.pen1);
pen2 = (LinearLayout) findViewById(R.id.pen2);
pen3 = (LinearLayout) findViewById(R.id.pen3);
pen4 = (LinearLayout) findViewById(R.id.pen4);
remove=(ImageView)findViewById(R.id.remove);
/*
* pen1.setOnClickListener(this); pen2.setOnClickListener(this);
* pen3.setOnClickListener(this); pen4.setOnClickListener(this);
*/
pen.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
pens.setVisibility(View.VISIBLE);
}
});pens.setVisibility(View.GONE);
pen1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_1);
pens.setVisibility(View.GONE);
}
});
pen2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_2);
pens.setVisibility(View.GONE);
}
});
pen3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
pens.setVisibility(View.GONE);
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_3);
}
});
pen4.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
pens.setVisibility(View.GONE);
mDrawView.setPen(SingleTouchView.DrawingPens.PEN_4);
}
});
remove.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
}
});
}
}
package com.example.singletouch;
import java.util.AbstractMap;
import java.util.Map;
import java.util.concurrent.ConcurrentLinkedQueue;
import android.R.color;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff.Mode;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.Switch;
public class SingleTouchView extends View{
public int width;
public int height;
public Bitmap mBitmap;
public Canvas mCanvas;
public Path mPath;
public Paint mBitmapPaint;
Context context;
public Paint circlePaint;
public Path circlePath;
public enum DrawingPens {
PEN_1(6),
PEN_2(4),
PEN_3(2),
PEN_4(1);
final public Paint mPaint;
/**
* Constructor
*
* @param width width of stroke
* @param color color of stroke
*/
private DrawingPens(final int width) {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(width);
//mPaint.setColor(color);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
}
/**
* @return corresponding paint
*/
Paint getPaint() {
return mPaint;
}
}
public SingleTouchView(final Context context) {
super(context);
init(context);
}
public SingleTouchView(final Context context, final AttributeSet attrs) {
super(context, attrs);
init(context);
}
public SingleTouchView(final Context context, final AttributeSet attrs, final int defStyle) {
super(context, attrs, defStyle);
init(context);
}
/** To store Paint - Path relation */
// TODO: depending on exact limits, more optimal ways can be found
private ConcurrentLinkedQueue<Map.Entry<Path, DrawingPens>> mPaths = new ConcurrentLinkedQueue<Map.Entry<Path, DrawingPens>>();
/** Cached current path, <b>NOTE:</b> this field is tail at mPaths and is used it only for caching, not drawing */
private Path mCurrentPath;
/**
* Inits internal views data, should be called from every constructor
*
* @param context {@link Context}
*/
private void init(final Context context) {
/* TODO: if some values of paints cannot be determined in static context (in enum),
then Paints should be created here and used via EnumMap */
// Initial pen
setPen(DrawingPens.PEN_1);
}
@Override
public void onDraw(Canvas canvas){
// just to draw background
super.onDraw(canvas);
// Draw all paths
for (Map.Entry<Path, DrawingPens> entry : mPaths) {
canvas.drawPath(entry.getKey(), entry.getValue().getPaint());
}
}
@Override
public boolean onTouchEvent(MotionEvent me){
float eventX = me.getX();
float eventY = me.getY();
switch (me.getAction()) {
case MotionEvent.ACTION_DOWN:
mCurrentPath.moveTo(eventX, eventY);
return true;
case MotionEvent.ACTION_MOVE:
mCurrentPath.lineTo(eventX, eventY);
break;
case MotionEvent.ACTION_UP:
break;
}
invalidate();
return true;
}
/**
* Setter for new pen
*
* @param pen {@link DrawingPens} to be used for next drawing
*/
public void setPen(final DrawingPens pen) {
// put latest item to the queue
mCurrentPath = new Path();
mPaths.add(new AbstractMap.SimpleImmutableEntry<Path, DrawingPens>(mCurrentPath, pen));
}
public void clear(View v){
}
}
package com.example.singletouch；
导入java.util.AbstractMap；
导入java.util.Map；
导入java.util.concurrent.ConcurrentLinkedQueue；
导入android.R.color；
导入android.content.Context；
导入android.graphics.Bitmap；
导入android.graphics.Canvas；
导入android.graphics.Color；
导入android.graphics.Paint；
导入android.graphics.Path；
导入android.graphics.PorterDuff.Mode；
导入android.util.AttributeSet；
导入android.view.MotionEvent；
导入android.view.view；
导入android.widget.ImageView；
导入android.widget.Switch；
公共类SingleTouchView扩展了视图{
公共整数宽度；
公众内部高度；
公共位图mBitmap；
公共画布mCanvas；
公共路径mPath；
公共涂料；
语境；
公共油漆；
公共道路环路；
公共枚举绘图笔{
围栏1（6），
围栏2（4），
围栏3（2），
围栏4（1）；
最终公共油漆；
/**
*建造师
*
*@param笔划宽度
*@param笔划颜色
*/
专用绘图笔（最终整数宽度）{
mPaint=新油漆（）；
mPaint.setAntiAlias（true）；
mPaint.设定行程宽度（宽度）；
//mPaint.setColor（颜色）；
mPaint.setStyle（油漆、样式、笔划）；
mPaint.setStrokeJoin（油漆.连接.圆形）；
}
/**
*@返回相应的油漆
*/
Paint getPaint（）{
返回mPaint；
}
}
公共SingleTouchView（最终上下文）{
超级（上下文）；
init（上下文）；
}
公共SingleTouchView（最终上下文、最终属性集属性）{
超级（上下文，attrs）；
init（上下文）；
}
公共SingleTouchView（最终上下文上下文、最终属性集属性、最终int-defStyle）{
超级（上下文、属性、定义样式）；
init（上下文）；
}
/**存储绘制路径关系的步骤*/
//TODO:根据具体的限制，可以找到更优化的方法
私有ConcurrentLinkedQueue MPath=新ConcurrentLinkedQueue（）；
/**缓存的当前路径，注意：此字段位于MPath的尾部，仅用于缓存，不用于绘图*/
专用路径mCurrentPath；
/**
*应该从每个构造函数调用Inits内部视图数据
*
*@param context{@link context}
*/
私有void init（最终上下文）{
/*TODO：如果无法在静态上下文中（在枚举中）确定某些绘制值，
然后，应在此处创建油漆，并通过EnumMap使用*/
//首笔
setPen（绘图笔。PEN_1）；
}
@凌驾
公共空白onDraw（画布）{
//只是画背景
super.onDraw（帆布）；
//绘制所有路径
用于（地图条目：百万帕）{
drawPath（entry.getKey（），entry.getValue（）.getPaint（））；
}
}
@凌驾
公共事件（MotionEvent me）{
float eventX=me.getX（）；
float eventY=me.getY（）；
开关（me.getAction（））{
case MotionEvent.ACTION\u DOWN：
mCurrentPath.moveTo（eventX，eventY）；
返回true；
case MotionEvent.ACTION\u移动：
mCurrentPath.lineTo（eventX，eventY）；
打破
case MotionEvent.ACTION\u UP：
打破
}
使无效（）；
返回true；
}
/**
*新笔的设定器
*
*@param pen{@link DrawingPens}用于下一次绘图
*/
公共无效设置笔（最终绘图笔）{
//将最新项目放入队列
mCurrentPath=新路径（）；
add（newAbstractMap.SimpleImmutableEntry（mCurrentPath，pen））；
}
公共空间清理（视图五）{
}
}
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
tools:context=".MainActivity" >
<com.example.singletouch.SingleTouchView
android:id="@+id/myview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_above="@+id/pen" />
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="@drawable/menubar"
android:padding="2dp"
android:weightSum="4" >
<ImageView
android:id="@+id/pen"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_alignParentBottom="true"
android:layout_weight="1"
android:gravity="center"
android:src="@drawable/pen" />
<ImageView
android:id="@+id/eraser"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_alignParentBottom="true"
android:layout_weight="1"
android:src="@drawable/eraser" />
<ImageView
android:id="@+id/color"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_alignParentBottom="true"
android:layout_weight="1"
android:src="@drawable/color" />
<ImageView
android:id="@+id/remove"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_alignParentBottom="true"
android:layout_weight="1"
android:src="@drawable/remove" />
</LinearLayout>
<LinearLayout
android:id="@+id/linear"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="@+id/linearLayout1"
android:layout_alignParentLeft="true"
android:background="#eeeeee"
android:orientation="horizontal"
android:visibility="gone"
android:weightSum="4" >
<LinearLayout
android:id="@+id/pen1"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_weight="1"
android:gravity="center" >
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:src="@drawable/pen1" />
</LinearLayout>
<LinearLayout
android:id="@+id/pen2"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_weight="1"
android:gravity="center" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:src="@drawable/pen2" />
</LinearLayout>
<LinearLayout
android:id="@+id/pen3"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_weight="1"
android:gravity="center" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="@drawable/pen3" />
</LinearLayout>
<LinearLayout
android:id="@+id/pen4"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_weight="1"
android:gravity="center" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="@drawable/pen4" />
</LinearLayout>
</LinearLayout>
</RelativeLayout>
将要清除的屏幕部分放在xml格式的单个布局中，例如
<RelativeLayout
android:id="@+id/layout"
android:layout_width="wrap_content"
android:layout_height= "wrap_content">
The Views that have to be gone on click
</RelativeLayout>
图像视图((ImageView) findViewById(R.id.imageView)).setImageDrawable(null);
mCanvas.drawColor(Color.BLACK);
remove.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// clear canvas contents
mCanvas.drawColor(Color.BLACK);
// create new path list; old one will be garbage collected
ConcurrentLinkedQueue<Map.Entry<Path, DrawingPens>> mPaths =
new ConcurrentLinkedQueue<Map.Entry<Path, DrawingPens>>();
pens.setVisibility(View.VISIBLE);
}
希望这有助于。。。干杯 您可以绘制透明色，而不是绘制纯色，这有助于您在将其他视图用作画布背景时不覆盖它们
remove.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
layout.removeView(mDrawView);
mDrawView = new SingleTouchView(MainActivity.this);
layout.addView(mDrawView);
}
});
mCanvas.drawColor（Color.TRANSPARENT，PorterDuff.Mode.CLEAR）
我从这个答案中得到了这个答案：我不知道你的意思，但也许这会有所帮助：@yser2617212-m发布我的xml文件，以便你了解。。。