根据已上线的app里总结出来的实用小技巧

BaseActivity基类的使用, 还有很多例如:BaseFragment、BaseService等等就不一一列举了

每个app必备(可以根据自己需求来自己定义, 或增加)#####

public abstract class BaseActivity extends AppCompatActivity implements View.OnClickListener {
    /** 当前Activity名字 */
    protected static String ACTIVITY_NAME;
    protected Bundle savedInstanceState;
    public Context context;
    public MissBearApplication application;
    /** 屏幕宽高, 状态栏高  */
    public int screenWidth, screenHeight, statusBarHeightX;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.savedInstanceState = savedInstanceState;
        LogUtils.i(ACTIVITY_NAME = getClass().getSimpleName());
        context = this;
        application = (MissBearApplication) getApplication();
        screenWidth = ScreenManager.getScreenSize(context)[0];
        screenHeight = ScreenManager.getScreenSize(context)[1];
        statusBarHeightX = ScreenManager.getStatusBarHeight(context);
        ActivityCollector.addActivity(this);

        setContentView();
        initData();
        initView();
        initListener();
    }

    @Override
    public void onBackPressed() {
        finish();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        isActivityFinish = true;
        ActivityCollector.removeActivity(this);
        finish();
    }

    public Toast toast;
    public void showToast(String text) {
        if (toast == null) {
            toast = Toast.makeText(context, text, Toast.LENGTH_SHORT);
        } else {
            toast.setText(text);
        }
        toast.show();
    }

    public void showToast(BaseActivity activity, String text) {
        if (toast == null) {
            toast = Toast.makeText(activity, text, Toast.LENGTH_SHORT);
        } else {
            toast.setText(text);
        }
        toast.show();
    }

    /**
     * 显示带图片的Toast
     * @param text  需要显示的文字
     * @param imgId 需要显示的图片
     */
    public void showImageToast(String text, int imgId) {
        Toast toast = Toast.makeText(context, text, Toast.LENGTH_SHORT);
        toast.setText(text);
        LinearLayout toastView = (LinearLayout) toast.getView();
        toastView.setGravity(Gravity.CENTER);
        ImageView toastImg = new ImageView(context);
        toastImg.setLayoutParams(new LinearLayout.LayoutParams(dp2px(25), dp2px(25)));
        toastImg.setScaleType(ImageView.ScaleType.FIT_XY);
        toastImg.setImageResource(imgId);
        toastView.addView(toastImg, 0);
        toast.show();
    }

    public void showToast(int textId) {
        showToast(getString(textId));
    }

    public BaseActivity getActivity() {
        return this;
    }

    public Intent getIntent(Class clazz) {
        return new Intent(context, clazz);
    }

    public void startIntent(Class clazz) {
        startActivity(getIntent(clazz));
    }

    public int dp2px(int dp) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,
                context.getResources().getDisplayMetrics());
    }

    protected void hideStatusBar() {
        int flag = WindowManager.LayoutParams.FLAG_FULLSCREEN;//隐藏状态栏, 定义全屏参数
        Window window = getWindow(); //获得当前窗体对象
        window.setFlags(flag, flag);//设置当前窗体为全屏显示
    }

    private long lastClickTime;
    /**
     * 实现连续点击两次才退出应用程序
     */
    public void exit() {
        if ((System.currentTimeMillis() - lastClickTime) > 2000) {
            showToast("再按一次退出" + context.getResources().getString(R.string.app_name));
            lastClickTime = System.currentTimeMillis();
        } else {
            ActivityCollector.removeAll();
            System.exit(0);
        }
    }

    @Override
    public void onClick(View v) {
        //继承了BaseActivity的类, 如果要使用返回关闭Activity的功能
        //需要在继承的Activity的onClick(View v)里写上super.onClick(v);
        switch (v.getId()) {
            case R.id.ll_back:
                //R.id.back为标题左上角的返回控件
                onBackPressed();
                break;

            default:
                break;
        }
    }

    public abstract void setContentView();

    public abstract void initView();

    public abstract void initListener();

    public abstract void initData();
}

使用方式#####

public class UpdateNickNameActivity extends BaseActivity implements View.OnClickListener {
    private LinearLayout ll_clear_nickname;

    @Override
    public void setContentView() {
        setContentView(R.layout.activity_update_nickname);
    }

    @Override
    public void initView() {
        //控件初始化
        ll_clear_nickname = (LinearLayout) findViewById(R.id.ll_clear_nickname );
    }

    @Override
    public void initListener() {
        //监听器设置
        ll_clear_nickname.setOnClickListener(this);
    }

    @Override
    public void initData() {
        //数据初始化
    }

    public void onClick(View v) {
        super.onClick(v);
        switch (v.getId()) {
            case R.id.ll_clear_nickname:
                //其他功能
                break;
        }
    }
}