Unity5 AssetBundle系列——资源加载卸载以及AssetBundleManifest的使用

Unity5 AssetBundle系列——资源加载卸载以及AssetBundleManifest的使用
　　下面代码列出了对于assetbundle资源的常用操作，其中有针对bundle、asset、gameobject三种类型对象的操作，实际使用中尽量保证成对使用。

这一块的操作比较繁琐，但只要使用正确，是可以保证资源完全没有泄露的。

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using UnityEngine;
using System.Collections;

public class TestAssetBundle : MonoBehaviour
{
public string AssetBundleName = “cube1.assetbundle”;

private string dir = "";
private AssetBundle bundle = null;
private UnityEngine.Object asset = null;
private GameObject go = null;

private void Start() { dir = Application.dataPath + "/StreamingAssets/"; }

private void OnGUI()
{
    // 这些操作一遍走下来，申请的资源是可以完全回收的
    if (GUILayout.Button("LoadAssetBundle", GUILayout.Width(200), GUILayout.Height(50))) { LoadBundle(); }
    if (GUILayout.Button("LoadAsset", GUILayout.Width(200), GUILayout.Height(50))) { LoadAsset(); }
    if (GUILayout.Button("Instantiate", GUILayout.Width(200), GUILayout.Height(50))) { Instantiate(); }
    if (GUILayout.Button("Destroy", GUILayout.Width(200), GUILayout.Height(50))) { Destroy(); }
    if (GUILayout.Button("Unload", GUILayout.Width(200), GUILayout.Height(50))) { Unload(); }
    if (GUILayout.Button("UnloadForce", GUILayout.Width(200), GUILayout.Height(50))) { UnloadForce(); }
    if (GUILayout.Button("UnloadUnusedAssets", GUILayout.Width(200), GUILayout.Height(50))) { UnloadUnusedAssets(); }
}

// 加载AssetBundle
private void LoadBundle()
{
    bundle = AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, AssetBundleName));
    if (bundle == null) Debug.LogError("LoadBundle Failed");
}

// 从AssetBundle加载Asset
private void LoadAsset()
{
    if (bundle == null) return;

    asset = bundle.LoadAsset("Cube1");
    if (asset == null) Debug.LogError("LoadAsset Failed");
}

// 根据Asset实例化GameObject
private void Instantiate()
{
    if (asset == null) return;

    go = GameObject.Instantiate(asset) as GameObject;
    if (go == null) Debug.LogError("Instantiate Failed");
}

// 销毁GameObject
private void Destroy()
{
    if (go == null) return;

    GameObject.Destroy(go);
    go = null;
}

// 弱卸载，释放AssetBundle本身的内存
private void Unload()
{
    if (bundle == null) return;

    // unload完，bundle就不能再用了，记得要置空
    bundle.Unload(false);
    asset = null;
    bundle = null;
}

// 强卸载（无视引用的卸载），释放AssetBundle本身的内存，同时回收从AssetBundle抽取的Asset
private void UnloadForce()
{
    if (bundle == null) return;

    // unload完，bundle就不能再用了，记得要置空
    bundle.Unload(true);
    asset = null;
    bundle = null;
}

// 全局弱卸载，回收无引用Asset
private void UnloadUnusedAssets()
{
    Resources.UnloadUnusedAssets();
}

}
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　　由于bundle相互之前会有依赖，所以在使用一个bundle包之前，需要先加载其依赖的所有bundle包，这个过程需要借助全局manifest来实现，简单代码如下：

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using UnityEngine;
using System.Collections;

public class TestManifest : MonoBehaviour
{
private string dir = “”;
private GameObject go = null;
private AssetBundleManifest manifest = null;

private void Start() { dir = Application.dataPath + "/StreamingAssets/"; }

private void OnGUI()
{
    if (GUILayout.Button("LoadAssetBundleManifest", GUILayout.Width(200), GUILayout.Height(50))) { LoadAssetBundleManifest(); }
    if (GUILayout.Button("LoadBundle", GUILayout.Width(200), GUILayout.Height(50))) { LoadBundle(); }
}

// 加载Manifest
private void LoadAssetBundleManifest()
{
    var bundle = AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, "StreamingAssets"));
    manifest = bundle.LoadAsset("AssetBundleManifest");
    // 压缩包释放掉
    bundle.Unload(false);
    bundle = null;
}

// 加载AssetBundle
private void LoadBundle()
{
    string bundleName = "assets.resources.test.cube1.prefab.assetbundle";
    // 注意：GetAllDependencies会返回直接和间接关联的AssetBundle
    //       加载依赖包没有顺序要求
    string[] dependence = manifest.GetAllDependencies(bundleName);
    for (int i = 0; i < dependence.Length; ++i )
    {
        AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, dependence[i]));
        // 注意：这里不需要手动LoadAsset
        //       只需要加载AssetBundle即可
        //       Asset会在加载其它关联Asset时自动加载
    }

    var bundle = AssetBundle.LoadFromFile(System.IO.Path.Combine(dir, bundleName));
    var asset = bundle.LoadAsset("Cube1");
    go = GameObject.Instantiate(asset) as GameObject;
}

}
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