Android直播软件搭建之实现背景颜色滑动渐变效果的详细代码

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我是靠谱客的博主靓丽大炮，这篇文章主要介绍Android直播软件搭建之实现背景颜色滑动渐变效果的详细代码，现在分享给大家，希望可以做个参考。

Android直播软件搭建实现背景颜色滑动渐变效果的相关代码

一、介绍一下GradientDrawable

GradientDrawable 支持渐变色的Drawable，与shapeDrawable是类似的，多了支持渐变色。
代码中的GradientDrawable比xml中的shape下gradient属性更加具体，shape下gradient属性只支持三色阶渐变，而GradientDrawable可以有更多的色阶渐变(GradientDrawable在Android中便是shape标签的代码实现)。

二、实现

1、在布局中放入一个ScrollView，然后确保里面的内容能够达到滑动的效果。

2、获取屏幕的高度

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//获取屏幕高度
private float getScreenHeight(){
DisplayMetrics metric = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metric);
int width = metric.widthPixels; // 屏幕宽度（像素）
int height = metric.heightPixels; // 屏幕高度（像素)
return height;
}

3、获取控件高度（此案例为ScrollView中包裹的第一个子控件）。
4、设置颜色(为了方便颜色自接写出来)

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Orientation.TOP_BOTTOM为纵向，横向改变参数即可
GradientDrawable aDrawable = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
new int[]{Color.parseColor("#ffffff"), Color.parseColor("#009966"),Color.parseColor("#00ff00")});
ll_base.setBackground(aDrawable);

5、获取控件与屏幕高度(宽度)的比例，根据比例设置颜色个数

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//得到控件的高度与屏幕高度的比例
private float getScreenHeightScale(int height){
return height/getScreenHeight();
}

三、源码：

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public class BaseActivity extends Activity {
private LinearLayout ll_base;
private int heights;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_base);
initView();
}

private void initView() {
ll_base = (LinearLayout) findViewById(R.id.ll_base);
}

@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
@Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);

heights = ll_base.getMeasuredHeight();
float coloramount=getScreenHeightScale(heights);
if (coloramount>=0&&coloramount<1.5f){
GradientDrawable aDrawable = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
new int[]{Color.parseColor("#ffffff"), Color.parseColor("#009966")});
ll_base.setBackground(aDrawable);
}
if (coloramount>=1.5f&&coloramount<3.0f){
GradientDrawable aDrawable = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
new int[]{Color.parseColor("#ffffff"), Color.parseColor("#009966"), Color.parseColor("#00ff00")});
ll_base.setBackground(aDrawable);
}
if (coloramount>=3.0f&&coloramount<4.5f){
GradientDrawable aDrawable = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
new int[]{Color.parseColor("#ffffff"), Color.parseColor("#009966"), Color.parseColor("#00ff00"),Color.parseColor("#000000")});
ll_base.setBackground(aDrawable);
}
// .................
}

//得到控件的高度与屏幕高度的比例
private float getScreenHeightScale(int height){
return height/getScreenHeight();
}
//获取屏幕高度
private float getScreenHeight(){
DisplayMetrics metric = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metric);
int width = metric.widthPixels; // 屏幕宽度（像素）
int height = metric.heightPixels; // 屏幕高度（像素)
return height;
}
}

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public class BaseActivity extends Activity {
private LinearLayout ll_base;
private int heights;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_base);
initView();
}


private void initView() {
ll_base = (LinearLayout) findViewById(R.id.ll_base);
}

 

@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
@Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);

heights = ll_base.getMeasuredHeight();
float coloramount=getScreenHeightScale(heights);
if (coloramount>=0&&coloramount<1.5f){
GradientDrawable aDrawable = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
new int[]{Color.parseColor("#ffffff"), Color.parseColor("#009966")});
ll_base.setBackground(aDrawable);
}
if (coloramount>=1.5f&&coloramount<3.0f){
GradientDrawable aDrawable = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
new int[]{Color.parseColor("#ffffff"), Color.parseColor("#009966"), Color.parseColor("#00ff00")});
ll_base.setBackground(aDrawable);
}
if (coloramount>=3.0f&&coloramount<4.5f){
GradientDrawable aDrawable = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
new int[]{Color.parseColor("#ffffff"), Color.parseColor("#009966"), Color.parseColor("#00ff00"),Color.parseColor("#000000")});
ll_base.setBackground(aDrawable);
}
// .................
}

//得到控件的高度与屏幕高度的比例
private float getScreenHeightScale(int height){
return height/getScreenHeight();
}
//获取屏幕高度
private float getScreenHeight(){
DisplayMetrics metric = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metric);
int width = metric.widthPixels; // 屏幕宽度（像素）
int height = metric.heightPixels; // 屏幕高度（像素)
return height;
}
}