Android----模仿ButterKnife的簡單實踐

摘要： 問題 在有贊實習，他們的程式碼中使用了很多butterknife的相關操作，於是實踐一下，簡單實現自己想象中的繫結與點選 思路 BindView簡化findViewById(R.id.xxx) BindClick簡化setOnClickListener(this); 0.繫...

問題

在有贊實習，他們的程式碼中使用了很多butterknife的相關操作，於是實踐一下，簡單實現自己想象中的繫結與點選

思路

BindView簡化findViewById(R.id.xxx)

BindClick簡化setOnClickListener(this);

0.繫結時兩個引數:Object host, View view。

1.遍歷宿主中的全部Field，為設定了BindView註解的新增findViewById

2.檢視宿主的BindClick，如果有，為BindClick中的變數設定setOnClickListener

效果

檔案結構

使用程式碼

MainActivity.java

@BindClick(ids ={
R.id.btnOne,
R.id.btnTwo,
R.id.btnThree
})
public class MainActivity extends AppCompatActivity implements View.OnClickListener{

@BindView(id = R.id.txt)
public TextView txt;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CopyButterKnife.bind(this, getWindow().getDecorView());

init();
}


private void init() {
txt.setText("hello copybutterknife");
getSupportFragmentManager().beginTransaction().add(R.id.container, new MainFragment()).commit();
}

public void onClick(View view){
int id = view.getId();
if (id == R.id.btnOne){
txt.setText("activity buttonOne Click");
} if (id == R.id.btnTwo){
txt.setText("activity buttonTwo Click");
} if (id == R.id.btnThree){
txt.setText("hello copybutterknife");
}
}
}

MainFragment.java

@BindClick(ids = {
R.id.btnOne,
R.id.btnTwo,
R.id.btnThree
})
public class MainFragment extends Fragment implements View.OnClickListener {

private View root;

@BindView(id = R.id.txt)
public TextView txt;

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
root = inflater.inflate(R.layout.fragment_main, null);
CopyButterKnife.bind(this, root);

init();
return root;
}

private void init(){
txt.setText("hello world");
}

@Override
public void onClick(View v) {
int id = v.getId();
if (id == R.id.btnOne){
txt.setText("fragment one click");
} else if (id == R.id.btnTwo){
txt.setText("fragment two click");
} else if (id == R.id.btnThree){
txt.setText("hello world");
}
}
}

工具程式碼

BindClick.java

@Retention(RetentionPolicy.RUNTIME)
public @interface BindClick {
int[] ids();
}

BindView.java

@Retention(RetentionPolicy.RUNTIME)
public @interface BindView {
int id();
}

CopyButterKnife.java

public class CopyButterKnife {

public static void bind(Object host, View view) {
Field[] fields = host.getClass().getFields();
for (Field field : fields) {
BindView bindView = field.getAnnotation(BindView.class);
if (bindView != null) {
try {
field.set(host, view.findViewById(bindView.id()));
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
}

BindClick bindClick = host.getClass().getAnnotation(BndClick.class);
if (bindClick != null) {
int[] ids = bindClick.ids();
for (int id : ids) {
view.findViewById(id).setOnClickListener((View.OnClickListener) host);
}
}
}
}

demo

ofollow,noindex">https://github.com/pgyCode/CopyButterKnife