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在Android开发中,有时利用seekbar实现相关的图片的旋转与缩放;
这里就简单介绍一下,如何利用seekbar实现图片的放大与缩小;以及旋转。
这是布局代码:
<?xml version="1.0" encoding="utf-8"?>
<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"
tools:context=".MainActivity">
<ImageView
android:id="@+id/iv_1"
android:layout_width="250dp"
android:layout_height="250dp"
android:layout_marginTop="16dp"
android:src="@drawable/onmk"
android:adjustViewBounds="true"
android:layout_gravity="center"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/tv_1"
android:layout_width="305dp"
android:layout_height="38dp"
android:layout_marginStart="8dp"
android:layout_marginTop="12dp"
android:layout_marginEnd="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/iv_1" />
<SeekBar
android:id="@+id/sb_1"
android:layout_width="match_parent"
android:layout_height="31dp"
android:layout_marginTop="12dp"
android:progress="120"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tv_1" />
<TextView
android:id="@+id/tv_2"
android:layout_width="300dp"
android:layout_height="38dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toTopOf="@+id/sb_2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/sb_1"
app:layout_constraintVertical_bias="0.666" />
<SeekBar
android:id="@+id/sb_2"
android:layout_width="match_parent"
android:layout_height="31dp"
android:layout_marginStart="4dp"
android:layout_marginTop="60dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/sb_1" />
</android.support.constraint.ConstraintLayout>
主函数中的代码:
package com.example.wuluo.wlht;
/**
* Created by wuluo on 2019/3/9
*/
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.DisplayMetrics;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;
import android.graphics.Matrix;
public class MainActivity extends AppCompatActivity implements SeekBar.OnSeekBarChangeListener {
private ImageView iv_1;
private SeekBar sb_1,sb_2;
private Matrix matrix;
private TextView tv_1,tv_2;
private int minWidth = 80;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv_1=(ImageView) findViewById(R.id.iv_1);
sb_1=(SeekBar)findViewById(R.id.sb_1);
sb_2=(SeekBar)findViewById(R.id.sb_2);
tv_1=(TextView)findViewById(R.id.tv_1);
tv_2=(TextView)findViewById(R.id.tv_2);
sb_1.setOnSeekBarChangeListener(this);
sb_2.setOnSeekBarChangeListener(this);
matrix=new Matrix();
//屏幕宽度
DisplayMetrics dm=new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int screen=dm.widthPixels;
//设置硕放滑动最大值
sb_1.setMax(screen);
sb_2.setMax(365);
}
@Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
if(seekBar.getId()==R.id.sb_1){
int newWidth = i + minWidth;
int newHeight = (int) (newWidth * 3 / 4);//按照原图片的比例缩放
iv_1.setLayoutParams(new LinearLayout.LayoutParams(newWidth, newHeight));
tv_1.setText("图像宽度:" + newWidth + " 图像高度:" + newHeight);
/*int ivWidth=i;
int ivHeight=i*3/4;
iv_1.setLayoutParams(new LinearLayout.LayoutParams(ivWidth,ivHeight));*/
}else if (seekBar.getId()==R.id.sb_2){
float d=i;
matrix.setRotate(d);
Bitmap bitmap=BitmapFactory.decodeResource(getResources(),R.drawable.bnvx);
Bitmap bitmap1 = bitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
iv_1.setImageBitmap(bitmap1);
tv_2.setText(i+"度");
}
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
}
实现效果:
样式挺简单的,效果也比较简单,
目前只是针对一张图片,后面会添加其他功能!