PinView 二次采样比例 ImageView 错误答案

【问题标题】：PinView Subsampling Scale ImageView ERRORPinView 二次采样比例 ImageView 错误
【发布时间】：2018-04-15 19:18:08
【问题描述】：

大家好，我正在尝试使用这个库 (https://github.com/davemorrissey/subsampling-scale-image-view)，我尝试了提到的有关 PinView 的示例，但我没有显示地图，也没有显示任何标记。（报错说cannot cast Subsampling ImageView as PinView 你怎么解决这个问题？

MainActivity.java

package com.ascot.mxiv.mapzone;

import android.graphics.PointF;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView;
import com.davemorrissey.labs.subscaleview.ImageSource;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    PinView imageView = findViewById(R.id.imageView);
    imageView.setImage(ImageSource.resource(R.drawable.completemap1).tilingDisabled());
    imageView.setPin(new PointF(460f, 320f));

}

}

PinView.java（除了导入 test.T.drawable 没有做任何更改，因为我不明白）和帮助将不胜感激：D。

import android.content.Context;
import android.graphics.*;
import android.util.AttributeSet;
import android.widget.Toast;

import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView;
//import com.davemorrissey.labs.subscaleview.test.R.drawable;

public class PinView extends SubsamplingScaleImageView {

private final Paint paint = new Paint();
private final PointF vPin = new PointF();
private PointF sPin;
private Bitmap pin;
Context context;

public PinView(Context context) {
    this(context, null);
    this.context = context;
}

public PinView(Context context, AttributeSet attr) {
    super(context, attr);
    this.context = context;
    initialise();
}

public void setPin(PointF sPin) {
    this.sPin = sPin;
    initialise();
    invalidate();
}

private void initialise() {
    float density = getResources().getDisplayMetrics().densityDpi;
    pin = BitmapFactory.decodeResource(this.getResources(), R.drawable.marker);
    float w = (density/420f) * pin.getWidth();
    float h = (density/420f) * pin.getHeight();
    pin = Bitmap.createScaledBitmap(pin, (int)w, (int)h, true);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    // Don't draw pin before image is ready so it doesn't move around during setup.
    if (!isReady()) {
        return;
    }

    paint.setAntiAlias(true);

    if (sPin != null && pin != null) {
        sourceToViewCoord(sPin, vPin);
        float vX = vPin.x - (pin.getWidth()/2);
        float vY = vPin.y - pin.getHeight();
        canvas.drawBitmap(pin, vX, vY, paint);
        Toast.makeText(context,"works ? ", Toast.LENGTH_SHORT).show();
    }

}

}

【问题讨论】：

为什么密度除以420f？

标签： java android marker

【解决方案1】：

问题出在您的布局中，您应该使用 PinView 而不是 SubsamplingScaleImageView，如下面的 sn-p 所示。

<com.example.myapp.PinView
    android:id="@+id/floorplan_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

【讨论】：