安卓：滚动型在画布上绘图(Android: Drawing on Canvas in Scrollv

2019-06-23 22:19发布

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我在编程的Android非常新。 我的应用是从API演示示例应用程序开发者的Android的网站。 当我说样品图中修改参数就变大。 那图纸需要（它并不需要进行收缩来适应屏幕）显示在滚动视图。 这是我使用的代码：

DrawPoints.java 

    public class DrawPoints extends myActivity {


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.routes); 

    }

    public static class SampleView extends View {
        private Paint   mPaint = new Paint();
        private float[] mPts;

       /*here comes declaration of parametars



        private void buildPoints() {

        /*here comes some coding*/

            }
        }

        public SampleView(Context context, AttributeSet attributeset) {
            super(context, attributeSet);

            buildPoints();
        }

        @Override 
        protected void onDraw(Canvas canvas) {
            Paint paint = mPaint;

            //here also comes code
        }
    }
}

这里是XML代码：

routes.xml 

<?xml version="1.0" encoding="utf-8"?>
    <ScrollView 
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/scrollView1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" >
        <HorizontalScrollView 
                android:id="@+id/scrollView2"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent">

                    <!-- This code is just to make sure that scroll views work how 
                        I want them to work, image size is 625*351 px
                     <ImageView
                        android:id="@+id/image_View1"
                        android:layout_width="fill_parent"
                        android:layout_height="fill_parent"
                        android:src="@drawable/bus_design"
                            /> -->
                     <my.package.DrawPoints.SampleView
                        android:layout_width="fill_parent" 
                        android:layout_height="fill_parent" /> 


        </HorizontalScrollView>
    </ScrollView>

当我运行该应用程序，并在主要活动中的应用程序崩溃按下按钮。 当我不使用XML布局或scrollviews绘图像如图一长相：

http://i.stack.imgur.com/za5MP.png 如图一

我也试过法的setContentView后，使用此代码： 

View v = new SampleView(this);
addContentView(v, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,
            ViewGroup.LayoutParams.FILL_PARENT));

而且这一个： 

View v = new SampleView(this);
    ScrollView.LayoutParams lp = new ScrollView.LayoutParams(1000, 1000);

    addContentView(v, lp);

当我使用码，如上图所示，应用程序显示如图一无滚动视图，它似乎是第二内容视图覆盖该XML，但它不正确显示。 从那以后，我试过的setContentView后使用此代码： 

View v = new SampleView(this);
    FrameLayout fl = new FrameLayout(this);
    fl.findViewById(R.id.FrameLayout1);
    fl.addView(v);

帧布局（FrameLayout1）在水平滚动视图后routes.xml文件被添加。 当应用程序运行时，我得到的空白屏幕，不如图一。 没有任何人有一个想法如何升级我的代码，将滚动型显示如图一？

提前致谢！

Answer 1:

在自定义视图类的TouchEvent此线

的getParent（）。requestDisallowInterceptTouchEvent（真）



Answer 2:

终于让我找到解决我的问题。 我使用这个网站的解决方案：

链接1

还有我之前看到的解决方案，但不幸的是我没有意识到，这种解决方案是为我好。 我知道我需要onMeasure方法画布在XML中表现出来，但withouth的从提到的站点解决方案没有奏效。 现在，它的工作原理。 这是我的XML和SampleView解决方案。

XML代码： 

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/app_layout" android:orientation="horizontal"
    android:layout_width="fill_parent" android:layout_height="fill_parent">
    <!-- SCENE -->
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/scene_layout" 
        android:drawingCacheQuality="low"
        android:orientation="horizontal" android:layout_width="fill_parent"
        android:layout_height="fill_parent">
        <com.testiranje.Kristijan.TwoDScrollView
            android:id="@+id/scene_scroller" android:drawingCacheQuality="low"
            android:scrollbars="horizontal"

            android:layout_width="fill_parent" android:layout_height="fill_parent">
            <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/scene_container" 
                android:drawingCacheQuality="low"
                android:background="@drawable/map"
                android:layout_width="fill_parent" android:layout_height="fill_parent">

                <com.testiranje.Kristijan.SampleView
                    android:layout_height="fill_parent"
                    android:layout_width="fill_parent">

                    </com.testiranje.Kristijan.SampleView>

                <!--  <ImageView xmlns:android="http://schemas.android.com/apk/res/android"
                    android:id="@+id/scene_background" android:drawingCacheQuality="low"
                    android:background="@drawable/map"
                    android:layout_width="fill_parent" android:layout_height="fill_parent" /> -->
            </RelativeLayout>
        </com.testiranje.Kristijan.TwoDScrollView>
    </RelativeLayout>
</RelativeLayout>

这是我的SampleView的解决方案： 

 public class SampleView extends View {
    private Paint   mPaint = new Paint();
    private float[] mPts;

    private static final float SIZE = 1000;
    private static final int SEGS = 50;
    private static final int X = 0;
    private static final int Y = 1;

    private void buildPoints() {
        final int ptCount = (SEGS + 1) * 2;
        mPts = new float[ptCount * 2];

        float value = 0;
        final float delta = SIZE / SEGS;
        for (int i = 0; i <= SEGS; i++) {
            mPts[i*4 + X] = SIZE - value;
            mPts[i*4 + Y] = 0;
            mPts[i*4 + X + 2] = 0;
            mPts[i*4 + Y + 2] = value;
            value += delta;
        }
    }

    public SampleView(Context context){
        super(context);
        //initSampleView();
        buildPoints();

    }

   //This constructor is very important because withouth of this 
   //you can't insert this view in xml
   public SampleView(Context context, AttributeSet attrs) {
        super(context, attrs);
        //initSampleView();
        buildPoints();
    }

    /*private final void initSampleView() {
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        setPadding(3, 3, 3, 3);
    }*/

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(measureWidth(widthMeasureSpec),
                measureHeight(heightMeasureSpec));
    }

    /**
     * Determines the width of this view
     * @param measureSpec A measureSpec packed into an int
     * @return The width of the view, honoring constraints from measureSpec
     */
    private int measureWidth(int measureSpec) {
        int result = 0;
        //This is because of background image in relativeLayout, which is 1000*1000px
        measureSpec = 1001;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);

        if (specMode == MeasureSpec.UNSPECIFIED) {
            // We were told how big to be
            result = specSize;
        }

        return result;
    }

    /**
     * Determines the height of this view
     * @param measureSpec A measureSpec packed into an int
     * @return The height of the view, honoring constraints from measureSpec
     */
   private int measureHeight(int measureSpec) {
        int result = 0;
        //This is because of background image in relativeLayout, which is 1000*1000px 
        measureSpec = 1001;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);


        if (specMode == MeasureSpec.UNSPECIFIED) {
            // Here we say how Heigh to be
            result = specSize;
        } 
        return result;
    }

    @Override 
    protected void onDraw(Canvas canvas) {
        Paint paint = mPaint;

        canvas.translate(10, 10);

        paint.setColor(Color.RED);
        paint.setStrokeWidth(0);
        canvas.drawLines(mPts, paint);


        paint.setColor(Color.BLUE);
        paint.setStrokeWidth(3);
        canvas.drawPoints(mPts, paint);

    }
}

现在，我得到了这个形象，当我运行我的应用程序：

http://i.stack.imgur.com/lWhvT.png

如果任何人有问题，这个随时问我:)。



文章来源: Android: Drawing on Canvas in Scrollview
标签： android scrollview drawing2d
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