折叠式标题栏的使用——复习笔记

之前看过《第二行代码》里面第十二章讲到过CoordinatorLayout、AppBarLayout、CollapsingToolbarLayout、NestedScrollView的使用，现在再复习一下，把原来的代码放在现在的项目中，首先创建布局activity_news_detail.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appBar"
        android:layout_width="match_parent"
        android:layout_height="250dp"
        android:fitsSystemWindows="true">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:statusBarScrim="@android:color/holo_orange_dark"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:contentScrim="@android:color/holo_orange_dark"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/newsImageView"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="true"
                android:scaleType="centerCrop"
                app:layout_collapseMode="parallax"/>

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"/>
        </android.support.design.widget.CollapsingToolbarLayout>
    </android.support.design.widget.AppBarLayout>

    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="15dp"
                android:layout_marginLeft="15dp"
                android:layout_marginRight="15dp"
                android:layout_marginTop="35dp"
                app:cardCornerRadius="4dp">

                <TextView
                    android:id="@+id/newsContentText"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_margin="10dp"/>
            </android.support.v7.widget.CardView>
        </LinearLayout>

    </android.support.v4.widget.NestedScrollView>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/floatingActionButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:src="@drawable/icon_textsize"
        app:layout_anchor="@id/appBar"
        app:layout_anchorGravity="bottom|end"/>

</android.support.design.widget.CoordinatorLayout>

然后是具体的代码NewsDetailActivity.class：

public class NewsDetailActivity extends AppCompatActivity{

    private CollapsingToolbarLayout collapsingToolbar;
    private FloatingActionButton floatingActionButton;
    private ImageView newsImageView;
    private TextView newsContentText;
    private Toolbar toolbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_news_detail);
        initView();
        initData();
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
//        getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
    }

    private void initView(){
        toolbar = (Toolbar)findViewById(R.id.toolbar);
        collapsingToolbar = (CollapsingToolbarLayout)findViewById(
                R.id.collapsing_toolbar);
        newsImageView = (ImageView)findViewById(R.id.newsImageView);
        newsContentText = (TextView)findViewById(R.id.newsContentText);
        floatingActionButton = (FloatingActionButton) findViewById(R.id.floatingActionButton);
        floatingActionButton.setOnClickListener(new MyOnClickListener());
        setSupportActionBar(toolbar);
        ActionBar actionBar = getSupportActionBar();
        if(actionBar != null){
            actionBar.setDisplayHomeAsUpEnabled(true);
        }
    }

    public void initData(){
        String allData = getIntent().getStringExtra("Content");
        Spanned result;
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {  //版本大于24的时候
            result = Html.fromHtml(allData, Html.FROM_HTML_MODE_LEGACY);
        } else {
            result = Html.fromHtml(allData);
        }
        String title = getIntent().getStringExtra("Title");
        String url = getIntent().getStringExtra("ImageUrl");
//        LogUtil.e(data);
        collapsingToolbar.setTitle(title);
        newsContentText.setText(result);
        newsContentText.setTextSize(20);
        Glide.with(this).load(url)
                .diskCacheStrategy(DiskCacheStrategy.ALL)
                .placeholder(R.drawable.default_pic)
                .error(R.drawable.default_pic)
                .into(newsImageView);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case android.R.id.home:
                finish();
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

    private class MyOnClickListener implements View.OnClickListener{

        @Override
        public void onClick(View v) {
            showChangeTextSizeDialog();
        }
    }
    private int tempSize = 2;
    private int realSize = tempSize;

    private void showChangeTextSizeDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("设置文字大小");
        String[] items = new String[]{"超大字体", "大字体", "正常字体", "小字体", "超小字体"};
        builder.setSingleChoiceItems(items, realSize, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                tempSize = which;
            }
        });
        builder.setNegativeButton("取消", null);
        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                realSize = tempSize;
                changeTextSize(realSize);
            }
        });
        builder.show();
    }

    private void changeTextSize(int realSize) {
        switch (realSize){
            case 0://超大字体
                newsContentText.setTextSize(50);
                break;
            case 1://大字体
                newsContentText.setTextSize(35);
                break;
            case 2://正常字体
                newsContentText.setTextSize(20);
                break;
            case 3://小字体
                newsContentText.setTextSize(15);
                break;
            case 4://超小字体
                newsContentText.setTextSize(10);
                break;
            default:
        }
    }
}

很多细节暂时先不写了。
然后是效果：