Compatibility of High version API in low version

Directly on the example, see how to avoid crash.

Eg: Gets the total space size of the partition on which this path resides, based on the given path.

Document Description: To obtain the file system usage, in the API level 9 and above the system, you can directly invoke File the relevant methods of the object, the following need to calculate their own

API level 9 and above, File.getTotalSpace() can be called, but the system object below API Level 8 File does not exist for this method

As follows

 /**   * Returns the total size in bytes of the Partition containing this path. * Returns 0 If this path does not exist. * *   @param   path *   @return   */ public  static  long   Gettotalspace (File path) { if  (Path = = Span style= "color: #0000ff;" >null   return  -1;  return   Path.gettotalspace ();}  

If minSdkVersion set to 8, then the build will report the following error:

Call requires API level 9 (current min is 8)

In order to compile can pass, can add @SuppressLint("NewApi") or @TargeApi(9) .

@TargeApi($API_LEVEL)the API level required to explicitly indicate the method, but not @SuppressLint("NewApi") ;

But this only can be compiled through, to the API Level8 system run, will be thrown java.lang.NoSuchMethodError .

The right approach

In order to run without error, you need:

1. Determine the runtime version, this method is not called in the low-version system

2. In order to ensure the integrity of the function, we need to provide the low-version function

As follows:

/*** Returns The total size in bytes of the partition containing this path. * Returns 0 If this path is does not exist. * * @paramPath *@return-1 means path is NULL, and 0 means path is not exist.*/@TargetApi (build.version_codes. Gingerbread)//using @TargeApi instead of @SuppressLint ("Newapi")@SuppressWarnings ("Deprecation") Public Static Longgettotalspace (File path) {if(Path = =NULL) {        return-1; }    if(Build.VERSION.SDK_INT >=Build.version_codes. Gingerbread) {returnPath.gettotalspace (); }    //implements Gettotalspace () in API lower than gingerbread    Else {        if(!path.exists ()) {            return0; } Else {            FinalStatFs stats =NewStatFs (Path.getpath ()); //Using deprecated method in the low API level system,//Add @SuppressWarnings ("description") to suppress the warning            return(Long) Stats.getblocksize () * (Long) Stats.getblockcount (); }    }}

Summarize:

1. Use to @TargeApi($API_LEVEL) make can be compiled through, not recommended @SuppressLint("NewApi") ;
2. Run-time judgment API level; This method is called only in an API level system that is high enough to have this method;
3. Ensure functional integrity and ensure that low API versions provide functionality through other methods.

Compatibility of High version API in low version