OnDraw中没有得到所谓的从视图布局派生的自定义视图 [英] onDraw not getting called for a custom view derived from view in layout

问题描述

我有一个自定义视图
.........

I have a custom view .........

package com.yasir.canvasTest;


import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.util.Log;
import android.view.View;


public class GraphView extends View {

    private static final String TAG = "GraphView";
    public static boolean BAR = true;
    public static boolean LINE = false;

    private Paint paint;
    private float[] values;
    private String[] horlabels;
    private String[] verlabels;
    private String title;
    private boolean type;
    public Canvas tmpCanvas = null;

    public GraphView(Context context, float[] values, String title, String[] horlabels, String[] verlabels) {
        super(context);
        //setScrollContainer(true);
        Log.v(TAG,"On GraphView==>");




        paint = new Paint();

        setWillNotDraw(false);
        requestLayout();
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {




        Log.v(TAG,"<==On Draw");

/// drawing code here
        invalidate();
    }

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.v(TAG,"On onMeasure==>");
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int parentWidth = MeasureSpec.getSize(widthMeasureSpec);
        int parentHeight = MeasureSpec.getSize(heightMeasureSpec);
        setMeasuredDimension(
                parentWidth * 2, parentHeight);
    }

}

...............
活动：的onCreate
...............

............... Activity: onCreate ...............

setContentView(R.layout.horscroll);

HorizontalScrollView hsView = (HorizontalScrollView) findViewById(R.id.hzsv);

LinearLayout ll = (LinearLayout) findViewById(R.id.linearParent);
ll.removeAllViews();


// create custom view and add to laywout
GraphView graphView = new GraphView(this, values, "GraphViewDemo",horlabels, verlabels, GraphView.LINE);


hsView.requestLayout();
hsView.setWillNotDraw(false);

ll.requestLayout();
ll.setWillNotDraw(false);
ll.addView(graphView);

.....................
XML
....................

..................... Xml ....................

<?xml version="1.0" encoding="utf-8"?>

<HorizontalScrollView
 android:id="@+id/hzsv"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout android:id="@+id/linearParent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"></LinearLayout>
 </HorizontalScrollView>

..................

..................

问候，
亚西尔·佩尔韦

Regards, Yasir Perwez

推荐答案

试着用层次浏览器这是怎么回事检查。我怀疑你的观点是没有得到画，因为它有一个0宽度，这可能是出于两个原因（一个或两个）：

Try checking with Hierarchy Viewer what's going on. I suspect your view is not getting drawn because it has a 0 width, and this could be for two reasons (either or both):

• 你没有设置任何 LinearLayout.LayoutParams 在自定义视图将它添加到布局之前，我不知道，如果默认的是的填写父之类;


• 您 onMeasure（）是不完整的，应该考虑到还是模式（ UNSPECIFIED ，完全， AT_MOST ）至极，将取决于从布局PARAMS了。有没有保证的getSize（）返回父母的大小，作为框架意味着，你应该甚至不知道如果出现这种情况。

• you're not setting any LinearLayout.LayoutParams on your custom view before adding it to the layout, and I'm not sure if the default ones are of the "fill parent" kind;
• your onMeasure() is incomplete, it should take into account also the mode (UNSPECIFIED, EXACTLY, AT_MOST) wich will depend from the layout params too. There's no guarantee that getSize() returns parent's size, and as the framework is meant, you shouldn't even know if that happens.

（@ slund的建议将可能是太有用）

(@slund's suggestion will probably be useful too)

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