我们今天学习的第一个是butterknife,我们之前有学习工他的依赖,而我们现在学的是他的自定义
来吧 开始第一部步
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface InjectView {
int ID();
}
第二部
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface OnClick {
int value();
}
第三部 在其次我们使用了反射的定义
public class ViewUtils {
public static void bind(Activity activity) {
bindFeild(activity);
bindOnClick(activity);
}
private static void bindOnClick(final Activity activity) {
Class<? extends Activity> clazz = activity.getClass();
Method[] declaredMethods = clazz.getDeclaredMethods();
for (final Method method : declaredMethods) {
OnClick annotation = method.getAnnotation(OnClick.class);
if (annotation != null) {
int value = annotation.value();
View view = activity.findViewById(value);
method.setAccessible(true);
try {
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
method.invoke(activity);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
private static void bindFeild(Activity activity) {
Class<? extends Activity> clazz = activity.getClass();
Field[] declaredFields = clazz.getDeclaredFields();
for (Field field : declaredFields) {
InjectView annotation = field.getAnnotation(InjectView.class);
if (annotation != null) {
int resID = annotation.ID();
View view = activity.findViewById(resID);
field.setAccessible(true);
try {
field.set(activity,view);
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
}
}
}
第五步在代码中如何使用:
现在我们写得是一个点击事件
public class MainActivity extends AppCompatActivity {
@InjectView(ID = R.id.button )
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ViewUtils.bind(this);
}
@OnClick(value = R.id.button)
private void OnClick(){
Toast.
makeText(MainActivity.this, "hello", Toast.LENGTH_SHORT).show();
}
}