Android基类的设计

这两天开始放寒假，在家呆着也是呆着，遂决定找星空以前 Android 方向大佬写的项目学习下，看看别人代码的结构以及有什么方法可以降低代码的耦合度，然后在师兄的项目里接触到了 BaseActivity，在这里记录一下

为什么设计基类#

方便代码编写，减少重复代码和冗余逻辑，优化代码
优化程序架构，降低耦合度，方便拓展、修改
版面更干净，减少了诸如生命周期日志等重复逻辑的占用版面

设计的基本思路#

生命周期的调试日志输出
绑定视图
常用 OnClick 方法
Back 方法，Toast 以及 Activity 等操作
常用第三方工具（ButterKnife 等）
标题栏是否显示，是否全屏，初始化数据等

具体基类的封装#

BaseActivity#

public abstract class BaseActivity<P extends BasePresenter> extends AppCompatActivity
        implements BaseView<P> {

    @BindView(R.id.toolbar)
    Toolbar mToolbar;

    Unbinder bind;

    /**
     * 进度对话框
     */
    protected ProgressDialog mProgressDialog;
    /**
     * 泛型确定Presenter
     */
    protected P mPresenter;

    @Override
    protected final void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 设置为竖屏
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        setContentView(bindLayout());
        // ButterKnife绑定布局
        bind = ButterKnife.bind(this);

        mPresenter = createPresenter();
        if (mPresenter != null) {
            // 调用Presenter初始化方法
            mPresenter.onStart();
        }

        // 准备数据
        prepareData();
        // 初始化标题栏
        initToolbar();
        // 初始化视图
        initView();
        // 初始化数据
        initData(savedInstanceState);
        // 初始化事件监听
        initEvent();
    }


    /**
     * 创建Presenter
     *
     * @return 泛型Presenter
     */
    protected abstract P createPresenter();

    /**
     * 实现BasePresenter接口的setPresenter方法
     *
     * @param presenter createPresenter()创建的Presenter
     */
    @Override
    public void setPresenter(P presenter) {
        mPresenter = presenter;
    }

    /**
     * 初始化Toolbar
     */
    private void initToolbar() {
        setSupportActionBar(mToolbar);
    }

    /**
     * 设置Toolbar标题
     *
     * @param title 标题
     */
    protected void setToolbarTitle(String title) {
        if (getSupportActionBar() != null) {
            getSupportActionBar().setTitle(title);
        }
    }

    /**
     * 设置Toolbar显示返回按钮及标题
     *
     * @param title 标题
     */
    protected void setToolbarBackEnable(String title) {
        if (getSupportActionBar() != null) {
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_arrow_white_24dp);
            setToolbarTitle(title);
        }

    }

    /**
     * 绑定布局
     *
     * @return 布局文件的资源ID
     */
    protected abstract int bindLayout();

    /**
     * 准备数据（从Intent获取上一个界面传过来的数据或其他需要初始化的数据）
     */
    protected abstract void prepareData();

    /**
     * 初始化视图，findViewById等等
     */
    protected abstract void initView();

    /**
     * 初始化数据，从本地或服务器开始获取数据
     *
     * @param savedInstanceState 界面非正常销毁时保存的数据
     */
    protected abstract void initData(Bundle savedInstanceState);

    /**
     * 初始化事件监听，setOnClickListener等等
     */
    protected abstract void initEvent();

    /**
     * 实现BaseView的showToast(CharSequence msg)
     *
     * @param msg 吐司显示的信息
     */
    @Override
    public void showToast(CharSequence msg) {
        ToastUtils.shortToast(this, msg);
    }

    /**
     * 实现BaseView的showToast(int msgId)
     *
     * @param msgId 吐司显示的字符串资源id
     */
    @Override
    public void showToast(int msgId) {
        ToastUtils.shortToast(this, msgId);
    }

    /**
     * 实现BaseView的showLoadingDialog(CharSequence msg)
     * 显示加载对话框
     *
     * @param msg 对话框的提示内容
     */
    @Override
    public void showLoadingDialog(CharSequence msg) {
        if (mProgressDialog == null) {
            mProgressDialog = new ProgressDialog(this);
            mProgressDialog.setTitle(R.string.title_dialog_tips);
            mProgressDialog.setMessage(msg);
        } else {
            mProgressDialog.setTitle(R.string.title_dialog_tips);
        }
        mProgressDialog.show();
    }

    /**
     * 实现BaseView的hideLoadingDialog()
     * 隐藏加载对话框
     */
    @Override
    public void hideLoadingDialog() {
        if (mProgressDialog != null && mProgressDialog.isShowing()) {
            mProgressDialog.dismiss();
        }
    }

    /**
     * Activity销毁时清理资源
     */
    @Override
    protected void onDestroy() {
        // ButterKnife解除绑定
        bind.unbind();
        // 销毁Presenter
        if (mPresenter != null) {
            mPresenter.onDestroy();
        }
        super.onDestroy();
    }

    /**
     * 隐藏键盘
     */
    public void hideKeyboard() {
        View view = getCurrentFocus();
        if (view != null) {
            ((InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE)).
                    hideSoftInputFromWindow(view.getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        // （仅有Activity的应用中SDK自动调用，不需要单独写）
        // 保证 onPageEnd 在onPause之前调用,因为 onPause 中会保存信息。
        MobclickAgent.onPageEnd(this.getClass().getSimpleName());
        MobclickAgent.onPause(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        //统计页面(仅有Activity的应用中SDK自动调用，不需要单独写。)
        MobclickAgent.onPageStart(this.getClass().getSimpleName());
        //统计时长
        MobclickAgent.onResume(this);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == android.R.id.home) {
            finish();
        }
        return super.onOptionsItemSelected(item);
    }
}

BaseFragment#

public abstract class BaseFragment<P extends BasePresenter> extends Fragment
        implements BaseView<P> {

    @BindView(R.id.toolbar)
    Toolbar mToolbar;

    private Unbinder mUnbinder;
    protected P mPresenter;

    protected ProgressDialog mProgressDialog;

    private ActionBar mActionbar;

    @Nullable
    @Override
    public final View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        mPresenter = createPresenter();
        if (mPresenter != null) {
            mPresenter.onStart();
        }
        View root = inflater.inflate(bindLayout(), container, false);
        mUnbinder = ButterKnife.bind(this, root);
        prepareData(savedInstanceState);
        initToolbar();
        // 初始化视图
        initView(root);
        initData(savedInstanceState);
        initEvent();
        return root;
    }


    protected abstract P createPresenter();


    @Override
    public void setPresenter(P presenter) {
        mPresenter = presenter;
    }

    /**
     * 准备数据
     *
     * @param savedInstanceState
     */
    protected abstract void prepareData(Bundle savedInstanceState);

    /**
     * 绑定fragment的布局文件
     *
     * @return
     */
    protected abstract int bindLayout();

    /**
     * 初始化数据
     *
     * @param savedInstanceState
     */
    protected abstract void initData(Bundle savedInstanceState);

    /**
     * 初始化界面
     *
     * @param rootView
     */
    protected abstract void initView(View rootView);

    /**
     * 初始化事件监听器
     */
    protected abstract void initEvent();


    /**
     * 初始化Toolbar
     */
    private void initToolbar() {
        ((AppCompatActivity) getActivity()).setSupportActionBar(mToolbar);
        mActionbar = ((AppCompatActivity) getActivity()).getSupportActionBar();
    }

    /**
     * 设置Toolbar标题
     *
     * @param title 标题
     */
    protected void setToolbarTitle(String title) {
        if (mActionbar != null) {
            mActionbar.setTitle(title);
        }
    }

    /**
     * 设置Toolbar显示返回按钮及标题
     *
     * @param title 标题
     */
    protected void setToolbarBackEnable(String title) {
        if (mActionbar != null) {
            mActionbar.setDisplayHomeAsUpEnabled(true);
            mActionbar.setHomeAsUpIndicator(R.drawable.ic_arrow_white_24dp);
        }
    }

    @Override
    public void showToast(CharSequence msg) {
        ToastUtils.shortToast(APP.getAppContext(), msg);
    }

    @Override
    public void showToast(int msgId) {
        ToastUtils.shortToast(APP.getAppContext(), msgId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Override
    public void showLoadingDialog(CharSequence msg) {
        if (mProgressDialog == null) {
            mProgressDialog = new ProgressDialog(getContext());
            mProgressDialog.setMessage(msg);
        } else {
            mProgressDialog.setTitle(R.string.title_dialog_tips);
        }
        mProgressDialog.show();
    }

    @Override
    public void hideLoadingDialog() {
        if (mProgressDialog != null && mProgressDialog.isShowing()) {
            mProgressDialog.dismiss();
        }
    }

    @Override
    public void onDetach() {
        mUnbinder.unbind();
        super.onDetach();
    }

    @Override
    public void onDestroyView() {
        if (mPresenter != null) {
            mPresenter.onDestroy();
        }
        super.onDestroyView();
    }

    @Override
    public void onResume() {
        super.onResume();
        MobclickAgent.onPageStart(this.getClass().getSimpleName());
    }

    @Override
    public void onPause() {
        super.onPause();
        MobclickAgent.onPageEnd(this.getClass().getSimpleName());
    }

}

BasePresenter#

public interface BasePresenter {

    void onStart();

    void onDestroy();

}

BaseView#

public interface BaseView<P> {

    void setPresenter(P presenter);

    void showToast(CharSequence msg);

    void showToast(int msgId);

    void showLoadingDialog(CharSequence msg);

    void hideLoadingDialog();

}

Impl 类#

public abstract class BasePresenterImpl implements BasePresenter {
    protected CompositeDisposable mSubscriptions;

    @Override
    public void onStart() {
        if (mSubscriptions == null) {
            mSubscriptions = new CompositeDisposable();
        }
    }

    @Override
    public void onDestroy() {
        if (mSubscriptions != null) {
            mSubscriptions.dispose();
            mSubscriptions.clear();
        }
    }
}

APP 类#

用于获取全局的 context

public class APP extends Application {

    private static Context appContext;
    private static long exitTime = 0;

    /**
     * 获取Application的Context
     *
     * @return 全局Context
     */
    public static Context getAppContext() {
        return appContext;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        appContext = getApplicationContext();
    }

    /**
     * 退出APP
     */
    public static void exitApp() {
        if (System.currentTimeMillis() - exitTime > 2000) {
            ToastUtils.shortToast(getAppContext(), appContext.getString(R.string.text_press_again));
            exitTime = System.currentTimeMillis();
        } else {
            android.os.Process.killProcess(android.os.Process.myPid());
        }
    }
}

具体使用#

Contract 契约类#

契约类用于定义同一个界面的 view 和 presenter 的接口，通过规范的方法命名或注释，可以清晰的看到整个页面的逻辑。

public interface myContract {

    interface View extends BaseView<Presenter> {
    }

    interface Presenter extends BasePresenter {

    }
}

Presenter#

public class SamplePresenter extends BasePresenterImpl implements myContract.Presenter {

    private final myContract.View mView;
    public SamplePresenter(myContract.View view) {
        mView = view;
        this.mView.setPresenter(this);
    }
}

Activiy#

public class SampleActivity extends BaseActivity<myContract.Presenter> implements myContract.View {

    @BindView(R.id.tv_sample_text)
    TextView mTvSample;

    @Override
    protected myContract.Presenter createPresenter() {
        return new SamplePresenter(this);
    }

    @Override
    protected int bindLayout() {
        //TODO:添加视图，记得添加androidmanifest
        return R.layout.activity_sample;
    }

    @Override
    protected void prepareData() {
        //TODO:准备数据 比如：从数据库加载数据，或者网络请求数据等等
    }

    @Override
    protected void initView() {
        //TODO:初始化视图 比如：recycleview的准备，添加adapter等等
        mTvSample.setText("这是一个sample");
    }

    @Override
    protected void initData(Bundle savedInstanceState) {
        //TODO:初始化数据 比如：将数据加入到view中
    }

    @Override
    protected void initEvent() {
        //TODO:初始化事件监听 比如：增加监听器，下拉刷新，加载更多等等
    }
}