尝试绘制自定义视图时崩溃-InflateException

Question

I have tried searching for this issue. I have seen similar experiences in other questions but they were working with different resources. I am attempting to draw a rectangle on screen with which to perform different actions based on clicking different buttons. I'm still pretty new to Android so any help would be appreciated. My preview looks fine, exactly like what I'm trying to do, but crashes in the emulator.

I am trying to draw a rectangle in my activity. I created a custom view class that is supposed to draw a triangle. I then tried to add that view to my content_main.xml but it throws the inflateException error.

ColorRectView class:

public class ColorRectView extends View {

private Rect rectangle;
private Paint paint;

public ColorRectView(Context context) {
    super(context);
    int x = 50;
    int y = 50;
    int sideLength = 200;

    // Create a rectangle to hold the random color
    rectangle = new Rect(x, y, sideLength, sideLength);

    // Create the Paint and set it's color
    paint = new Paint();
    paint.setColor(Color.GRAY);
}

@Override
protected void onDraw(Canvas canvas) {
    canvas.drawRect(rectangle, paint);
}

content_main.xml

<android.support.constraint.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"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context=".MainActivity"
tools:showIn="@layout/activity_main">

<colorRectPractice.ColorRectView
    android:id="@+id/colorRectangle"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

// This was the original view container that I added using the design tab, gave me the same error
    <!--<view-->
    <!--class="colorRectPractice.ColorRectView"-->
    <!--id="@+id/view4"-->
    <!--android:layout_width="wrap_content"-->
    <!--android:layout_height="wrap_content"-->
    <!--tools:layout_editor_absoluteX="74dp"-->
    <!--tools:layout_editor_absoluteY="178dp" />-->


</android.support.constraint.ConstraintLayout>

I'm getting this error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{colorRectPractice/colorRectPractice.MainActivity}: android.view.InflateException: Binary XML file line #23: Binary XML file line #17: Error inflating class colorRectPractice.ColorRectView
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
    at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4754)
    at android.app.ActivityThread.-wrap18(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1599)
    at android.os.Handler.dispatchMessage(Handler.java:105)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6541)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
 Caused by: android.view.InflateException: Binary XML file line #23: Binary XML file line #17: Error inflating class xyz.softdev.colorswipe.ColorRectView
 Caused by: android.view.InflateException: Binary XML file line #17: Error inflating class xyz.softdev.colorswipe.ColorRectView
 Caused by: java.lang.NoSuchMethodException: <init> [class android.content.Context, interface android.util.AttributeSet]
    at java.lang.Class.getConstructor0(Class.java:2320)
    at java.lang.Class.getConstructor(Class.java:1725)
    at android.view.LayoutInflater.createView(LayoutInflater.java:615)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:790)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
    at android.view.LayoutInflater.parseInclude(LayoutInflater.java:995)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:859)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
    at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287)
    at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
    at xyz.softdev.colorswipe.MainActivity.onCreate(MainActivity.java:22)
    at android.app.Activity.performCreate(Activity.java:6975)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
    at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4754)
    at android.app.ActivityThread.-wrap18(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1599)
    at android.os.Handler.dispatchMessage(Handler.java:105)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6541)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

Answer 1

you are missing AttributeSet in your custom view constructor.

Here is an Example of making simple Piechart.

 import android.content.Context; import android.content.res.TypedArray; import android.graphics.BlurMaskFilter; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Path; import android.graphics.RadialGradient; import android.graphics.RectF; import android.graphics.Shader.TileMode; import android.util.AttributeSet; import android.view.View; import com.talview.recruit.R; public class DonutChart extends View { private float radius; Paint paint; Paint shadowPaint; Path myPath; Path shadowPath; RectF outterCircle; RectF innerCircle; RectF shadowRectF; public DonutChart(Context context, AttributeSet attrs) { super(context, attrs); TypedArray a = context.getTheme().obtainStyledAttributes( attrs, R.styleable.DonutChart, 0, 0 ); try { radius = a.getDimension(R.styleable.DonutChart_radius, 20.0f); } finally { a.recycle(); } paint = new Paint(); paint.setDither(true); paint.setStyle(Paint.Style.FILL); paint.setStrokeJoin(Paint.Join.ROUND); paint.setStrokeCap(Paint.Cap.ROUND); paint.setAntiAlias(true); paint.setStrokeWidth(radius / 14.0f); shadowPaint = new Paint(); shadowPaint.setColor(0xf0000000); shadowPaint.setStyle(Paint.Style.STROKE); shadowPaint.setAntiAlias(true); shadowPaint.setStrokeWidth(4.0f); shadowPaint.setMaskFilter(new BlurMaskFilter(4, BlurMaskFilter.Blur.SOLID)); myPath = new Path(); shadowPath = new Path(); outterCircle = new RectF(); innerCircle = new RectF(); shadowRectF = new RectF(); float adjust = (.019f*radius); shadowRectF.set(adjust, adjust, radius*2-adjust, radius*2-adjust); adjust = .038f * radius; outterCircle.set(adjust, adjust, radius*2-adjust, radius*2-adjust); adjust = .276f * radius; innerCircle.set(adjust, adjust, radius*2-adjust, radius*2-adjust); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); // green setGradient(0xff84BC3D,0xff5B8829); drawDonut(canvas,paint, 0,60); //red setGradient(0xffe04a2f,0xffB7161B); drawDonut(canvas,paint, 60,60); // blue setGradient(0xff4AB6C1,0xff2182AD); drawDonut(canvas,paint, 120,60); // yellow setGradient(0xffFFFF00,0xfffed325); drawDonut(canvas,paint, 180,180); } public void drawDonut(Canvas canvas, Paint paint, float start,float sweep){ myPath.reset(); myPath.arcTo(outterCircle, start, sweep, false); myPath.arcTo(innerCircle, start+sweep, -sweep, false); myPath.close(); canvas.drawPath(myPath, paint); } public void setGradient(int sColor, int eColor){ paint.setShader(new RadialGradient(radius, radius, radius-5, new int[]{sColor,eColor}, new float[]{.6f,.95f},TileMode.CLAMP) ); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int desiredWidth = (int) radius*2; int desiredHeight = (int) radius*2; int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int width; int height; //70dp exact if (widthMode == MeasureSpec.EXACTLY) { width = widthSize; }else if (widthMode == MeasureSpec.AT_MOST) { //wrap content width = Math.min(desiredWidth, widthSize); } else { width = desiredWidth; } //Measure Height if (heightMode == MeasureSpec.EXACTLY) { height = heightSize; } else if (heightMode == MeasureSpec.AT_MOST) { height = Math.min(desiredHeight, heightSize); } else { height = desiredHeight; } //MUST CALL THIS setMeasuredDimension(width, height); } } 

Answer 2

You must declare the multiple constructors in your ColorRectView

constructor(context: Context)
constructor(context: Context, attrSet : AttributeSet)
constructor(context: Context, attrSet: AttributeSet, defStyleAttributeSet : Int)