android获取本地版本号

た入场券 2022-08-08 16:59 223阅读 0赞

android获取本地版本号，并保存到本地文件。

/**
    	 * 获取当前版本号
    	 * @return
    	 */
    	public String getNowVersion(){
    		String version = "";
    		
    		FileInputStream in = null;
    		ByteArrayOutputStream bout = new ByteArrayOutputStream();  
            byte[]buf = new byte[1024];  
            int length = 0;  
    		try {
    			in = openFileInput(ConstantUtil.fileName);  // version.txt
    				while ((length = in.read(buf)) != -1) {
    					bout.write(buf, 0, length);
    				}
    				byte[] content = bout.toByteArray();
    				version = new String(content, "UTF-8");
    				version = version.split("=")[1];
    			try {
    				in.close();
    				bout.close();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}  
    		} catch (FileNotFoundException e) {
    			// 文件不存在则新建文件，并获取当前版本写到文件中
    			PackageManager manager = this.getPackageManager();
    			PackageInfo info = null;
    			try {
    				info = manager.getPackageInfo(this.getPackageName(), 0);
    			} catch (NameNotFoundException ne) {
    				ne.printStackTrace();
    			}
    			version = info.versionName;
    			saveVersion("version=" + version);
    		} catch (IOException e) {
    			e.printStackTrace();
    		} 
    		
    		return version;
    	}
    	
    	/**
    	 * 保存版本号到文件
    	 * @param content
    	 */
    	public void saveVersion(String content){
    		FileOutputStream out = null;  
            try {  
                out = openFileOutput(ConstantUtil.fileName, Context.MODE_PRIVATE);  
                out.write(content.getBytes("UTF-8"));  
            } catch (Exception e) {  
                e.printStackTrace();  
            }  
            finally{  
                try {  
                    out.close();  
                } catch (Exception e) {  
                    e.printStackTrace();  
                }  
            }  
    	}