seekbar 自定义图片上下左右显示不全 / bitmapToDrawable / bitmapToDrawable互转 / paddingStart/paddingEnd /thumbOffset

progressDrawable的高度设置

android:maxHeight="20dp"
android:minHeight="20dp"

maxHeight/minHeight : 进度条高度

thumboffset 来设置滑块可超出轨道距离

padding来设置轨道在view中位置

splitTrack : 滑块是否使用父布局背景色，true使用，默认false

解决滑块图片显示不全：

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.PixelFormat;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.SeekBar;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

@SuppressLint("AppCompatCustomView")
public class ScaleThumbSeekBar extends SeekBar {
    
    private static final String TAG = ScaleThumbSeekBar.class.getSimpleName();

    public ScaleThumbSeekBar(@NonNull Context context) {
    
        this(context, null);
    }

    public ScaleThumbSeekBar(@NonNull Context context, @Nullable AttributeSet attrs) {
    
        this(context, attrs, -1);
    }

    public ScaleThumbSeekBar(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    
        super(context, attrs, defStyleAttr);

    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    
        super.onSizeChanged(w, h, oldw, oldh);

        //解决滑动图片上下显示不全
        Drawable thumb = getThumb();
        Bitmap bitmap = drawableToBitmap(thumb);
        Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, h, h, true);
        BitmapDrawable bitmapDrawable = bitmapToDrawable(scaledBitmap, getContext());
        setThumb(bitmapDrawable);

        //解决滑动图片左右显示不全
        setThumbOffset(0);
        setPadding(0, 0, 0, 0);
    }

    //调用函数缩小图片
    public BitmapDrawable getNewDrawable(Context context, int restId, int dstWidth, int dstHeight) {
    
        Bitmap decodeResource = BitmapFactory.decodeResource(context.getResources(), restId);
        Bitmap scaledBitmap = Bitmap.createScaledBitmap(decodeResource, dstWidth, dstHeight, true);
        BitmapDrawable bitmapDrawable = bitmapToDrawable(scaledBitmap, context);
        Bitmap bitmap = bitmapDrawable.getBitmap();
        if (bitmap.getDensity() == Bitmap.DENSITY_NONE) {
    
            bitmapDrawable.setTargetDensity(context.getResources().getDisplayMetrics());
        }
        return bitmapDrawable;
    }

    public BitmapDrawable bitmapToDrawable(Bitmap bitmap, Context context) {
    
        return new BitmapDrawable(context.getResources(), bitmap);
    }

    private Bitmap drawableToBitmap(Drawable drawable) {
    
        if (drawable instanceof BitmapDrawable) {
    
            Log.e(TAG, "drawableToBitmap: BitmapDrawable ");
            BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
            return bitmapDrawable.getBitmap();
        } else {
    
            Log.e(TAG, "drawableToBitmap: ! BitmapDrawable ");
            int width = drawable.getIntrinsicWidth();
            int height = drawable.getIntrinsicHeight();
            drawable.setBounds(0, 0, width, height);

            Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ?
                    Bitmap.Config.ARGB_8888 :
                    Bitmap.Config.RGB_565;
            Bitmap bitmap = Bitmap.createBitmap(width, height, config);
            Canvas canvas = new Canvas(bitmap);
            drawable.draw(canvas);

            return bitmap;
        }
    }
}

demo

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@android:color/black" android:gravity="center" android:orientation="vertical">


    <SeekBar android:id="@+id/seek_bar" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:background="@android:color/white" />

    <!-- thumbOffset ：默认按压放大时滑块可超出轨道的距离 -->

    <SeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="30dp" android:background="@android:color/white" android:thumbOffset="20dp" />

    <SeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:thumbOffset="0dp" />

    <SeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:thumbOffset="-20dp" />

    <!-- paddingStart/paddingEnd ：轨道的边距 -->

    <SeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="30dp" android:background="@android:color/white" android:paddingStart="0dp" android:paddingEnd="0dp" />

    <SeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:paddingStart="15dp" android:paddingEnd="15dp" />

    <SeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:paddingStart="25dp" android:paddingEnd="25dp" />


    <!-- android:splitTrack : 滑块是否使用父布局背景色，true使用，默认false -->

    <com.xq.myapplication.ScaleThumbSeekBar android:id="@+id/seekBar" android:layout_width="match_parent" android:layout_height="20dp" android:layout_marginHorizontal="50dp" android:layout_marginTop="30dp" android:background="@android:color/white" android:progressDrawable="@drawable/progress_drawable" android:thumb="@mipmap/ic_launcher" />

    <com.xq.myapplication.ScaleThumbSeekBar android:layout_width="match_parent" android:layout_height="20dp" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:progressDrawable="@drawable/progress_drawable" android:splitTrack="true" android:thumb="@mipmap/ic_launcher" />

    <com.xq.myapplication.ScaleThumbSeekBar android:layout_width="match_parent" android:layout_height="20dp" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:progressDrawable="@drawable/progress_drawable" android:splitTrack="false" android:thumb="@mipmap/ic_launcher" />

    <!-- android:maxHeight/minHeight : 进度条高度 -->

    <com.xq.myapplication.ScaleThumbSeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:maxHeight="20dp" android:minHeight="20dp" android:progressDrawable="@drawable/progress_drawable" android:splitTrack="true" android:thumb="@mipmap/ic_launcher" />

    <com.xq.myapplication.ScaleThumbSeekBar android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginHorizontal="50dp" android:layout_marginTop="10dp" android:background="@android:color/white" android:maxHeight="40dp" android:minHeight="40dp" android:progressDrawable="@drawable/progress_drawable" android:splitTrack="false" android:thumb="@mipmap/ic_launcher" />

</LinearLayout>

drawable/progress_drawable :

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@android:id/background">
        <shape>
            <solid android:color="#ff0000" />
        </shape>
    </item>

    <item android:id="@android:id/progress">
        <clip>
            <shape>
                <solid android:color="#0000ff" />
            </shape>
        </clip>
    </item>
</layer-list>

activity:

import androidx.appcompat.app.AppCompatActivity;

import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.widget.SeekBar;

public class MainActivity extends AppCompatActivity {
    
    private static final String TAG = MainActivity.class.getSimpleName();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SeekBar seekBar = findViewById(R.id.seek_bar);
        int thumbOffset = seekBar.getThumbOffset();
        Log.e(TAG, "onCreate:滑块可超出轨道======> " + thumbOffset);//23
        int thumbWidth = seekBar.getThumb().getIntrinsicWidth();
        Log.e(TAG, "onCreate:滑块宽度======> " + thumbWidth);//47
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN_MR1) {
    
            int paddingStart = seekBar.getPaddingStart();
            int paddingEnd = seekBar.getPaddingEnd();
            int paddingTop = seekBar.getPaddingTop();
            int paddingBottom = seekBar.getPaddingBottom();
            Log.e(TAG, "onCreate:轨道在view中左边距=============> " + paddingStart);//42
            Log.e(TAG, "onCreate:轨道在view中右边距=============> " + paddingEnd);//42
            Log.e(TAG, "onCreate:轨道在view中上边距=============> " + paddingTop);//0
            Log.e(TAG, "onCreate:轨道在view中下边距=============> " + paddingBottom);//0
// mSeekBar.setPadding(0, 0, 0, 0);
// mSeekBar.setThumbOffset(0);
        }

        getSystemVersions();
    }

    private void getSystemVersions() {
    
        // 系统API版本号-数字格式，例如：30，亦即表示Android API level 30
        int version = Build.VERSION.SDK_INT;
        // 系统版本号，例如：11，亦即表示Android 11
        String strRelease = Build.VERSION.RELEASE;
        Log.e(TAG, "androidApiVersion===" + version +
                ",androidVersion===" + strRelease);
    }
}

效果图：