Android之常用类型转换

这篇文章是记录我们平时在android开发过程中，经常会用到的类型转换，主要包括String、byte[]、bitmap、inputstram、Drawable之间的转换，代码如下：

<span style="font-size:18px;">import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

public class Demo {

	/**
	 * bitmap 转  byte[]数组
	 */
	public byte[] bitmap2byteArray(Bitmap bitmap){
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
		byte[] bytes = baos.toByteArray();
		return bytes;
	}

	/**
	 * bitmap 转  inputstream
	 */
	public InputStream bitmap2InputStream(Bitmap bitmap){
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
		InputStream is = new ByteArrayInputStream(baos.toByteArray());
		return is;
	}

	/**
	 * byte[]数组   转   bitmap
	 */
	public Bitmap byteArray2Bitmap(byte[] bytes){
		Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
		return bitmap;
	}

	/**
	 * inputstream  转   bitmap
	 */
	public Bitmap inputStream2Bitmap(InputStream is){
		Bitmap bitmap = BitmapFactory.decodeStream(is);
		return bitmap;
	}

	/**
	 * Drawable 转  bitmap
	 */
	public Bitmap drawable2Bitmap(Drawable img){
		BitmapDrawable bd = (BitmapDrawable) img;
		Bitmap bitmap = bd.getBitmap();
		return bitmap;
	}

	/**
	 * bitmap 转  Drawable
	 */
	public Drawable bitmap2Drawable(Bitmap bitmap){
		BitmapDrawable bd = new BitmapDrawable(bitmap);
		Drawable img = bd;
		return img;
	}

	/**
	 * String 转  byte[]数组
	 */
	public byte[] string2ByteArray(String str,String charset){
		byte[] bytes = null;
		if(charset == null){
			bytes = str.getBytes();
		}else{
			try {
				//如charset = "utf-8"
				bytes = str.getBytes(charset);
			} catch (Exception e) {
				// TODO: handle exception
			}

		}
		return bytes;
	}

	/**
	 * String 转  inputstream
	 */
	public InputStream string2InputStream(String str){
		InputStream is = new ByteArrayInputStream(str.getBytes());
		return is;
	}

	/**
	 * inputstream 转  String  方法01
	 */
	public String inputStream2String01(InputStream is) throws IOException{
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		int i = -1;
		while((i=is.read()) != -1){
			baos.write(i);
		}
		return baos.toString();
	}

	/**
	 * inputstream 转  String   方法02
	 */
	public String inputStream2String02(InputStream is) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(is));
		StringBuilder sb = new StringBuilder();
		String line = null;
		while((line=br.readLine()) != null){
			sb.append(line+"\n");
		}

		return sb.toString();
	}

	/**
	 * inputstream 转  String   方法03
	 */
	public String inputSteam2String03(InputStream is) throws IOException{
		StringBuilder sb = new StringBuilder();
		byte[] b =new byte[1024];
		for(int n; (n=is.read(b)) != -1;){
			String s = new String(b, 0, n);
			sb.append(s);
		}
		return sb.toString();
	}

}</span>

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