我看到两种解决此问题的方法,具体取决于您愿意做什么:
An Activity
必须正确启动,使用startActivity()
或任何变体。它还必须在您的清单中声明。因此,只有当您所有的情况下,以下内容才有效MyClass
变体具有相同的签名。
我假设你的启动代码位于Activity
。加载后立即classToLoad
,您可以执行以下操作:
final File tmpDir = getDir("dex", 0);
final String libPath = Environment.getExternalStorageDirectory() + "/test.jar";
final DexClassLoader classloader = new DexClassLoader(libPath, tmpDir.getAbsolutePath(), null, this.getClass().getClassLoader());
try {
final Class<Object> classToLoad = (Class<Object>) classloader.loadClass("org.shlublu.android.sandbox.MyClass");
// CHANGED: THIS STARTS PROPERLY YOUR ACTIVITY ONCE THE CLASS LOADED
final Intent intent = new Intent(this, classToLoad);
startActivity(intent);
} catch (ClassNotFoundException e) {
// handle that Exception properly here
}
现在改变doSomething()
在某种程度上它使用底层Context
你的新的Activity
代替getApplicationContext()
。然后从MyClass.onCreate()
例如,看看它是否有效:
public class MyClass extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
doSomething(); // CHANGED: just as an example
}
private void doSomething() {
// CHANGED: now the following line uses 'this' instead of `getApplicationContext()`
Toast.makeText(this, "MyClass: doSomething() called.", Toast.LENGTH_LONG).show();
Log.d(MyClass.class.getName(), "MyClass: doSomething() called.");
}
}
其余的 - 何时致电doSomething()
、为什么等等... - 完全取决于您愿意做什么。
无需创建另一个Activity
在这种情况下。doSomething()
只需要收到适当的Context
显示Toast
.
Change MyClass
如下:
public class MyClass {
private void doSomething(Context ctx) {
Toast.makeText(ctx, "MyClass: doSomething() called.", Toast.LENGTH_LONG).show();
Log.d(MyClass.class.getName(), "MyClass: doSomething() called.");
}
}
并更改您的启动代码以通过this
to doSomething()
,假设它是从Activity
:
final File tmpDir = getDir("dex", 0);
final String libPath = Environment.getExternalStorageDirectory() + "/test.jar";
final DexClassLoader classloader = new DexClassLoader(libPath, tmpDir.getAbsolutePath(), null, this.getClass().getClassLoader());
try {
final Class<Object> classToLoad = (Class<Object>) classloader.loadClass("org.shlublu.android.sandbox.MyClass");
// CHANGED: LOADS THE METHOD doSomething(Context). EXECUTES IT WITH this AS AN ARGUMENT
final Class[] args = new Class[1];
args[0] = Context.class;
final Method doSomething = classToLoad.getMethod("doSomething", args);
final Object myInstance = classToLoad.newInstance();
doSomething.invoke(myInstance, this);
} catch (ClassNotFoundException e) {
// handle that Exception properly here
}