Compatibility processing of the Android high-version API method on the low-version system

Android version replacement, new version brings new features, new methods.

The new approach brings a lot of convenience, but it can't run on a lower version of the system, and if the compatibility is not handled properly, the app will be crash on the lower version of the system.

This article shows a specific example of how to handle compatibility issues when using the High API level approach.

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

Referenced in the wirelessly file store usage reference:

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

General implementation

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

As in the following ways:

/** * Returns the total size in bytes of the partition containing this path. * Returns 0 if this path does not exist. *  * @param path * @return -1 means path is null, 0 means path is not exist. */public static long getTotalSpace(File path) {    if (path == null) {        return -1;    }    return path.getTotalSpace();}

Processing cannot be compiled by

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:

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

3. 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 does not exist. * * @param path * @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 long G    Ettotalspace (File path) {if (path = = null) {return-1; } if (Build.VERSION.SDK_INT >= build.version_codes.    Gingerbread) {return path.gettotalspace (); }//Implements Gettotalspace () in API lower than gingerbread else {if (!path.exists ()) {return        0;            } else {final StatFs stats = new StatFs (Path.getpath ()); Using deprecated method In low API level system,//Add @SuppressWarnings ("description") to suppress the WA        Rning return (Long) stats.getblocksize () * (long) stats.getblockcount (); }    }}

Summarize

Using a method higher than minSdkVersion the API level requires:

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.

Recommended:

Compatibility processing of the Android high-version API method on the low-version system