【框架】FloatingActionButton

效果图：

<!--
    app:backgroundTint="@color/colorPrimary"设置FAB的背景颜色，也可以通过<color name="colorAccent">#08f704</color>来设置
    app:fabSize="mini"设置FAB的大小，取值两种，mini-48dp,normal-56dp
    app:elevation="5dp"设置FAB的Z轴高度
    app:borderWidth="5dp"设置圆环的宽度
-->
<android.support.design.widget.FloatingActionButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="fabClick"
    app:borderWidth="5dp"
    app:elevation="5dp"
    app:fabSize="normal"/>

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="dismissSnackBar"/>

public class MainActivity extends AppCompatActivity {

    private Snackbar snackbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void fabClick(View view) {
//        Toast.makeText(MainActivity.this, "123", Toast.LENGTH_SHORT).show();
        //Snackbar.LENGTH_INDEFINITE一直显示
        snackbar = Snackbar.make(view, "HelloWorld", Snackbar.LENGTH_INDEFINITE).setAction("go", new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "456", Toast.LENGTH_SHORT).show();
            }
        }).setActionTextColor(Color.RED);

        //获取到显示HelloWorld的控件
        View view1 = snackbar.getView();
        view1.setBackgroundColor(Color.WHITE);
        TextView textView = (TextView) view1.findViewById(android.support.design.R.id.snackbar_text);
        textView.setTextColor(Color.BLUE);
        snackbar.show();
    }

    public void dismissSnackBar(View view) {
        snackbar.dismiss();
    }
}