Question

我想向状态栏和工具栏添加线性渐变颜色。我能够以0度的角度向状态栏和工具栏添加渐变，以显示从左到右的渐变颜色(pink on left and purple on right)。但是我想要90度角的梯度流，从上到下或从下到上(eg: top pink and bottom purple)。我尝试过，但最终还是这样。这里状态栏和工具栏是分开的，我想要两个状态栏和工具栏具有相同的渐变颜色，且渐变角度为90度

Answer 1

在KitKat及更高版本上，您可以通过将状态栏设置为半透明并使用带有稀松布的全屏布局来控制状态栏和操作栏背景，同时注意将渐变从状态栏混合到操作栏。

一个警告是，KitKat在我们自己的基础上使用了自己的渐变稀松布，似乎无法覆盖，但是在Lollipop +上则没有这样的问题。

以下是MarshMallow模拟器上的工作活动示例：

这是我使用的代码：

res / values / styles.xml：

<style name="AppTheme" parent="Theme.AppCompat.NoActionBar">
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="actionBarStyle">@style/MyActionBar</item>
</style>

<style name="MyActionBar" parent="@style/Widget.AppCompat.ActionBar">
    <item name="background">@drawable/actionbar_bg</item>
</style>

<style name="AppTheme.ActionBar.Popup" parent="ThemeOverlay.AppCompat">
    <item name="android:colorBackground">@color/colorPrimaryDark</item>
    <item name="background">@color/colorPrimaryDark</item>
</style>

res / values / colors.xml：

<resources>
    <color name="colorPrimary">#ff7000e0</color>
    <color name="colorPrimaryDark">#ff400080</color>
    <color name="colorAccent">#ff40aba0</color>
</resources>

res / drawable / statusbar_bg.xml：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="270"
        android:endColor="#ff7000e0"
        android:startColor="#ff8000ff" />
</shape>

res / drawable / actionbar_bg.xml：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:startColor="#ff7000e0"
        android:endColor="#ff400080"
        android:angle="270" />
</shape>

res / layout / activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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:orientation="vertical"
    android:fitsSystemWindows="false" >

    <View
        android:id="@+id/main_activityStatusBarScrim"
        android:layout_width="match_parent"
        android:layout_height="26dp"
        android:background="@drawable/statusbar_bg"/>

    <android.support.v7.widget.Toolbar
        android:id="@+id/main_activityToolbar"
        android:layout_width="match_parent"
        android:layout_height="?android:attr/actionBarSize"
        android:background="@drawable/actionbar_bg"
        app:popupTheme="@style/AppTheme.ActionBar.Popup"/>

    <FrameLayout
        android:id="@+id/main_activityFragmentContainer"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        android:background="#ffffffff">

    </FrameLayout>

</LinearLayout>

MainActivity.java：

public class MainActivity extends AppCompatActivity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // make the main layout fill the screen
        Window window = getWindow();
        final int layoutFlags = View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
        window.getDecorView().setSystemUiVisibility(layoutFlags);
        supportRequestWindowFeature(Window.FEATURE_ACTION_BAR_OVERLAY);

        // make the status bar translucent
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            window.setStatusBarColor(0x00000000);
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            // N.B. on some (most?) KitKat devices the status bar has a pre-defined gradient that
            // cannot be overridden.
            window.addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
        }

        // inflate main layout and set up action bar
        setContentView(R.layout.activity_main);
        Toolbar toolbar = findViewById(R.id.main_activityToolbar);
        if (toolbar != null) {
            setSupportActionBar(toolbar);
        }

        // set the height of the scrim to standard status bar height for this device (normally 26dp)
        View statusBarScrim = findViewById(R.id.main_activityStatusBarScrim);
        int height;
        int resourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
        if (resourceId > 0) {
            height = getResources().getDimensionPixelSize(resourceId);
        } else {
            // belt and braces 
            height = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 26f, getResources().getDisplayMetrics());
        }
        if (statusBarScrim != null) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                ViewGroup.LayoutParams lp = statusBarScrim.getLayoutParams();
                lp.height = height;
                statusBarScrim.setLayoutParams(lp);
                statusBarScrim.setVisibility(View.VISIBLE);
            }
        }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
    ...

在Android中从顶部到底部到状态栏和工具栏创建线性渐变

1 个答案: