版權(quán)聲明：本文為HaiyuKing原創(chuàng)文章，轉(zhuǎn)載請(qǐng)注明出處！

前言

用于縮放bitmap以及將bitmap保存成圖片到SD卡中

效果圖

代碼分析

bitmapZoomByHeight(Bitmap srcBitmap, float newHeight)： 根據(jù)指定的高度進(jìn)行縮放（src是bitmap）

bitmapZoomByHeight(Drawable drawable, float newHeight) ：根據(jù)指定的高度進(jìn)行縮放（src是drawable）

bitmapZoomByScale(Bitmap srcBitmap, float scaleWidth, float scaleHeight)： 根據(jù)指定的寬度比例值和高度比例值進(jìn)行縮放

drawableToBitmap(Drawable drawable) ：將drawable對(duì)象轉(zhuǎn)成bitmap對(duì)象

drawableToBitmap2(Drawable drawable) ：將drawable對(duì)象轉(zhuǎn)成bitmap對(duì)象

saveBitmapToSDCard(Bitmap bitmap, String path)： 將bitmap對(duì)象保存成圖片到sd卡中

getBitmapFromSDCard(String path) ：從sd卡中去除圖片的bitmap對(duì)象

使用步驟

一、項(xiàng)目組織結(jié)構(gòu)圖

?

注意事項(xiàng)：

1、? 導(dǎo)入類文件后需要change包名以及重新import R文件路徑

2、? Values目錄下的文件（strings.xml、dimens.xml、colors.xml等），如果項(xiàng)目中存在，則復(fù)制里面的內(nèi)容，不要整個(gè)覆蓋

二、導(dǎo)入步驟

將BitmapUtil復(fù)制到項(xiàng)目中

package com.why.project.bitmaputildemo.utils;import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Matrix; import android.graphics.PixelFormat; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.Drawable;import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream;/*** Created by HaiyuKing* Used*/public class BitmapUtil {public static Bitmap temp;/**根據(jù)指定的高度進(jìn)行縮放（source是bitmap）*/public static Bitmap bitmapZoomByHeight(Bitmap srcBitmap, float newHeight) {float scale = newHeight / (((float)srcBitmap.getHeight()));return BitmapUtil.bitmapZoomByScale(srcBitmap, scale, scale);}/**根據(jù)指定的高度進(jìn)行縮放（source是drawable）*/public static Bitmap bitmapZoomByHeight(Drawable drawable, float newHeight) {Bitmap bitmap = BitmapUtil.drawableToBitmap(drawable);float scale = newHeight / (((float)bitmap.getHeight()));return BitmapUtil.bitmapZoomByScale(bitmap, scale, scale);}/**根據(jù)指定的寬度比例值和高度比例值進(jìn)行縮放*/public static Bitmap bitmapZoomByScale(Bitmap srcBitmap, float scaleWidth, float scaleHeight) {int width = srcBitmap.getWidth();int height = srcBitmap.getHeight();Matrix matrix = new Matrix();matrix.postScale(scaleWidth, scaleHeight);Bitmap bitmap = Bitmap.createBitmap(srcBitmap, 0, 0, width, height, matrix, true);if(bitmap != null) {return bitmap;}else {return srcBitmap;}}/**將drawable對(duì)象轉(zhuǎn)成bitmap對(duì)象*/public static Bitmap drawableToBitmap(Drawable drawable) {int width = drawable.getIntrinsicWidth();int height = drawable.getIntrinsicHeight();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.setBounds(0, 0, width, height);drawable.draw(canvas);return bitmap;}/**將drawable對(duì)象轉(zhuǎn)成bitmap對(duì)象*/public static Bitmap drawableToBitmap2(Drawable drawable) {BitmapDrawable bd = (BitmapDrawable) drawable;Bitmap bm= bd.getBitmap();return bm;}/**將bitmap對(duì)象保存成圖片到sd卡中*/public static void saveBitmapToSDCard(Bitmap bitmap, String path) {File file = new File(path);if(file.exists()) {file.delete();}try {FileOutputStream fileOutputStream = new FileOutputStream(file);bitmap.compress(Bitmap.CompressFormat.PNG, 100, ((OutputStream)fileOutputStream));//設(shè)置PNG的話，透明區(qū)域不會(huì)變成黑色 fileOutputStream.close();System.out.println("----------save success-------------------");}catch(Exception v0) {v0.printStackTrace();}}/**從sd卡中獲取圖片的bitmap對(duì)象*/public static Bitmap getBitmapFromSDCard(String path) {Bitmap bitmap = null;try {FileInputStream fileInputStream = new FileInputStream(path);if(fileInputStream != null) {BitmapFactory.Options options = new BitmapFactory.Options();options.inSampleSize = 2; //當(dāng)圖片資源太大的適合，會(huì)出現(xiàn)內(nèi)存溢出。圖片寬高都為原來的二分之一，即圖片為原來的四分一bitmap = BitmapFactory.decodeStream(((InputStream) fileInputStream), null, options);}} catch(Exception e) {return null;}return bitmap;}}

在AndroidMainfest.xml文件中聲明權(quán)限

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"package="com.why.project.bitmaputildemo"><!-- =================BitmapUtil用到的權(quán)限========================== --><!-- 允許程序讀取外部存儲(chǔ)文件 --><uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/><!-- 允許程序?qū)懭胪獠看鎯?chǔ)，如SD卡上寫文件 --><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission><applicationandroid:allowBackup="true"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:supportsRtl="true"android:theme="@style/AppTheme"><activity android:name=".MainActivity"><intent-filter><action android:name="android.intent.action.MAIN"/><category android:name="android.intent.category.LAUNCHER"/></intent-filter></activity></application></manifest>

添加運(yùn)行時(shí)權(quán)限的處理（本demo中采用的是修改targetSDKVersion=22）

三、使用方法

本Demo搭配《AppDir【創(chuàng)建緩存目錄】》使用

package com.why.project.bitmaputildemo;import android.graphics.Bitmap; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.ImageView;import com.why.project.bitmaputildemo.utils.AppDir; import com.why.project.bitmaputildemo.utils.BitmapUtil;import java.io.File;public class MainActivity extends AppCompatActivity {private ImageView img_source;private ImageView img_scale1;private ImageView img_scale2;private Button btn_save;private Button btn_show;private ImageView img_show;private String pngFilePath;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initViews();initDatas();initEvents();}private void initViews() {img_source = (ImageView) findViewById(R.id.img_source);img_scale1 = (ImageView) findViewById(R.id.img_scale1);img_scale2 = (ImageView) findViewById(R.id.img_scale2);btn_save = (Button) findViewById(R.id.btn_save);btn_show = (Button) findViewById(R.id.btn_show);img_show = (ImageView) findViewById(R.id.img_show);}private void initDatas() {img_source.setImageResource(R.mipmap.ic_launcher);Bitmap sourceBitmap = BitmapUtil.drawableToBitmap(getResources().getDrawable(R.mipmap.ic_launcher));Bitmap sacleBitmap1 = BitmapUtil.bitmapZoomByHeight(sourceBitmap,200);img_scale1.setImageBitmap(sacleBitmap1);Bitmap sacleBitmap2 = BitmapUtil.bitmapZoomByScale(sourceBitmap,2,1);img_scale2.setImageBitmap(sacleBitmap2);}private void initEvents() {btn_save.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {pngFilePath = AppDir.getInstance(MainActivity.this).IMAGE + File.separator + System.currentTimeMillis() + ".png";Bitmap sourceBitmap = BitmapUtil.drawableToBitmap(getResources().getDrawable(R.mipmap.ic_launcher));BitmapUtil.saveBitmapToSDCard(sourceBitmap,pngFilePath);}});btn_show.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {String pngPath = pngFilePath;Bitmap pngBitmap = BitmapUtil.getBitmapFromSDCard(pngPath);img_show.setImageBitmap(pngBitmap);}});} }

混淆配置

無

參考資料

Android常用的Drawable和Bitmap之間的轉(zhuǎn)化方法

項(xiàng)目demo下載地址

https://github.com/haiyuKing/BitmapUtilDemo

轉(zhuǎn)載于:https://www.cnblogs.com/whycxb/p/7635940.html

與50位技術(shù)專家面對(duì)面20年技術(shù)見證，附贈(zèng)技術(shù)全景圖

總結(jié)

以上是生活随笔為你收集整理的BitmapUtil【缩放bitmap以及将bitmap保存成图片到SD卡中】的全部?jī)?nèi)容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網(wǎng)站內(nèi)容還不錯(cuò)，歡迎將生活随笔推薦給好友。