import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import com.android.annotationproject.util.BindView;
import com.android.annotationproject.util.OnClick;
import com.android.annotationproject.util.WyqBind;
public class MainActivity extends AppCompatActivity {
@BindView(R.id.btn_action)
private Button btnAction;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WyqBind.bind(this);
btnAction.setText("注解的实现依赖于java的反射机制");
}
@OnClick(R.id.btn_action)
public void onClick(View view) {
switch (view.getId()) {
case R.id.btn_action:
Toast.makeText(this, "按钮被点击了", Toast.LENGTH_SHORT).show();
break;
}
}
}
import android.app.Activity;
import android.support.annotation.NonNull;
import android.support.annotation.UiThread;
import android.view.View;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
public class WyqBind {
@NonNull
@UiThread
public static void bind(@NonNull Activity target) {
findViewById(target);
onClick(target);
}
private static void findViewById(Activity activity) {
Class<? extends Activity> clazz = activity.getClass();
Field[] declaredFields = clazz.getDeclaredFields();
for (int i = 0; i < declaredFields.length; i++) {
Field field = declaredFields[i];
BindView annotation = field.getAnnotation(BindView.class);
if (annotation != null) {
int viewId = annotation.value();
View view = activity.findViewById(viewId);
try {
field.setAccessible(true);
field.set(activity, view);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
private static void onClick(final Activity activity) {
Class<?> clazz = activity.getClass();
try {
final Method method = clazz.getMethod("onClick", View.class);
OnClick onClick = method.getAnnotation(OnClick.class);
if (onClick != null) {
int[] viewIds = onClick.value();
for (int viewId : viewIds) {
final View view = activity.findViewById(viewId);
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
method.setAccessible(true);
try {
method.invoke(activity);
} catch (Exception e) {
e.printStackTrace();
try {
method.invoke(activity, view);
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
});
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface OnClick {
int[] value();
}
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface BindView {
int value();
}