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片段保存视图状态

onsaveinstancestate android-fragments android-layout android

1

Alex · 技术社区 · 8 年前

我有一些碎片有这样的结构:

    <RelativeLayout
        android:id="@+id/control_panel"
        android:visibility="gone">

        <RelativeLayout
            android:id="@+id/control_panel_icon">

            <ImageView
                android:id="@+id/control_panel_icon_1"
                android:src="@drawable/ic_control_panel_icon_1" />

            <ImageView
                android:id="@+id/control_panel_icon_2"
                android:src="@drawable/ic_control_panel_icon_2"
                android:visibility="gone"/>
        </RelativeLayout>

        <TextView
            android:id="@+id/control_panel_tv"
            android:text="@string/not_available" />
    </RelativeLayout>

在碎片类中 onSaveInstanceState 和 onActivityCreated :

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putString("tv", panel_tv.getText().toString());
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    if (savedInstanceState != null) 
        panel_tv.setText(savedInstanceState.getString("tv"));
}

所以它解决了保存 TextView 是的。

在fragment类中,我还设置了要用某些函数显示的图像:

public void setIcon(boolean condition){
    if (condition) {
         control_panel_icon_1.setVisibility(View.GONE);
         control_panel_icon_2.setVisibility(View.VISIBLE);
    } else {
         control_panel_icon_1.setVisibility(View.VISIBLE);
         control_panel_icon_2.setVisibility(View.GONE);
    }
}

是否有方法保存和还原当前显示的图像?

我知道,我不应该保存整个小部件,但是如果我可以保存 RelativeLayout 它能恢复孩子的所有状态吗?

2 回复 | 直到 8 年前

1

2

Code-Apprentice 8 年前

在你的片段类中,声明一个私有变量:

private boolean condition; // rename to something more descriptive

现在在 setIcon() 存储值:

this.condition = condition;

最后把这个保存到包里 onSaveInstanceState() 以下内容:

outState.putBoolean("condition", this.condition);

把它读进去 onActivityCreated() :

this.condition = savedInstanceState.getBoolean("condition");
this.setIcon(this.condition);

注意

你不需要保存 TextView 是的。对…的呼唤 super.onSaveInstanceState() 已经帮你搞定了。

2

Mosius sMiLo 8 年前

你可以保存 condition 在里面 outState 如下所示:

outState.putBoolean("condition", condition);

然后阅读并更新图像视图

setIcon(savedInstanceState.getBoolean("condition"))

或者可以通过以下方式保存图像视图的可见性状态 putInt 方法:

outState.putInt("ic1", control_panel_icon_1.getVisibility());
outState.putInt("ic2", control_panel_icon_2.getVisibility());

然后恢复状态:

control_panel_icon_1.setVisibility(savedInstanceState.getInt("ic1"));
control_panel_icon_2.setVisibility(savedInstanceState.getInt("ic2"));